You can solve these level mismatches as described here:
https://www.forum.rme-audio.de/viewtopic.php?id=25399

Alternatively turn down volume of your monitors.

AFAIK RME dampens already the "switch-on clicks" on phones outputs on most of their interfaces.
Also on analog outputs with those: 802, UFX, UFX II and UFX+.

Maybe it helps you to
- reduce the output level of phones
- store it in each of your TM FX snapshots
- store it to your device if TM FX allows for that. BBFP has not 6 different setups like i.e. UCX, but maybe there is still a TM FX option which allows to store the current settings to the device. Check TM FX: Options -> Store Current Stare into Device)
- select in TM FX Preferences (F2)
  (x) Always init DSP devices with TotalMix FX settings
  by this the device will always be initialized by TM FX settings and it avoids the pop-up Window on boot
  whether you want to use the current devices settings or TM FX settings shall they differ.
- check in the Phones Output by clicking on the "tool symbol" whether your phones output supports different output levels.
From Handbook it appears to me they have only one level
I have for example on the UFX+ two levels "Low" and "High", where Low is fully sufficient for me, I need to reduce the volume still to -20dB, so that it's not to loud for a "sane" initial setting.
- You could plug your phones to the smaller 3,5mm phones output. According to manual they have different output:
DA, Phones 3/4
As DA Line Out, but:
Output: 6.3 mm TRS jack, unbalanced
Output impedance: 10 Ohm
Output level at 0 dBFS, 1 kOhm load: +13 dBu
Max power @ 0.1% THD: 50 mW
Output: 3.5 mm TRS jack, unbalanced
Output impedance: 2 Ohm
Output level at 0 dBFS, 1 kOhm load: +7 dBu
Max power @ 0.1% THD: 70 mW

Last alternative solution, get something like a monitor controller.
If I remember right solutions for this have been mentioned in the cited RME thread above.

The "Rolls Royce" solution would be, to use either ADI-2 Pro FS for excellend AD/DA convertion quality.
You can combine it nicely with the BBFP by connecting it via ADAT, see my blog:
https://www.tonstudio-forum.de/blog/ind … our-Setup/
https://www.tonstudio-forum.de/blog/ind … C3%A4rker/

Do you use an external power supply ? If not then pls try whether this makes a difference.

A pop sound on the phones output is expected with that unit. It's harmless, though.

Yes. MusicBee is also a fine player supporting ASIO as well.

I have been wrestling with this same issue. And as far as I can tell, it is a hardware level issue. If you have ever owned another audio interface with physical pots for volume, you know that keeping that knob in a volume  position  that works for your listening setup stays the same whether the unit is on or off. With the Babyface Pro, the volume is controlled via software. So when the clipping noise spike occurs, it's because the RME unit has lost its software memory of where the volume position was.

These fix methods suggested here seem to be workarounds. But a true fix would be the hardware, out of the box, storing the last volume position used in memory while powered down.

I don't have the external power supply for this unit, as it didn't come with one and I never knew of a performance advantage.

The preference setting checked, still allows an unrestricted signal 'pop' through the outputs (headphones, monitors, etc) on power off and on.

The 'store current state to device' is not available (greyed out setup options)

Exactly the same thing happens to me, I have my bios configured to turn off all usb ports, but when I turn off my BF PRO I get a pop that is heard in the distance coming out of the output of my headphones and is heard with the headphones on my desktop without having them placed on my head try to lower the volume of everything in total mix but it does not work.
Sometimes I think that if that pop can damage my headphones, I hope not, but I don't understand why such a prestigious brand hasn't paid attention to that detail, the same thing happened to me with my old scarlett interface, it had the same pops

Has anyone at RME thought of an update to fix this? It is an interface that I like and the price deserves it

This question has been answered several times correctly already, but since only half of the comments here seem to acknowledged it: it is not a defect with your unit, you have to just accept that this is how it works. Many people on this thread claiming that it's assuredly harmless to monitors / headphones plugged-in and I find that believable but don't want to find out the hard way so I have my (biamplified) monitors connected to a power strip which I use as an easy on/off switch to control both at once and if I need to start / restart my computer (or unplug the Babyface) I turn off my monitors using the power strip for a moment - I also do this when plugging in ADAT cables to the lightpipe I/O, though its a different sound. I assume the signal is within levels typical to regular output and has no capability to harm my monitors/headphones, as RME would have stated like 100 times in their excellent manuals to be careful of this.

I leave my USB ports powered. I have my powered monitors on the same mains switch as my pc. My volume on my monitors I never touch. When I power down the pc there is no pop. I then switch of the mains so all goes off at once. No pop. When I switch on again no pop. I then boot the pc and no pop. This method works well for me. The bfp is not always powered as I am removing power from the pc.