I previously had version 0.49.3 on Raspi 3B. After opening a patch and additionally opening the object overview window, it crashed. My guess is that the DSP opens 2x independent DAC output, which doesn't work due to the BCM2835's lack of hardware mixing. Current compiled version 0.53 (puredata.info) can represent this problem at least in the console, if you start it from there. XRuns occur, but the program does not crash. You clearly see, that ALSA restarts like crazy. You should also check in the second window whether the ALSA settings are correct and save them there if necessary. It's obviously a sound chip issue. For the object overview, however, I added a [loadbang]->[;pd dsp 0] message and saved it.
You can also turn off DSP before opening another patch (or subpatch!) that will automatically turn on DSP, which happens under the hood, e.g., the help patches. With these changes, so far, it works for me. Furthermore, a proper sound card with hardware mixing would solve the issue. You get the idea.

Hello,
I have a similar issue and I think I'm almost there to figure it out.
I've found this Miller Pucket Github's post : https://github.com/pure-data/pure-data/issues/969
But I don't know what to do with the code.

Can you help me please?

@Boris The fix mentioned in your link is 3 years old...... so if you have updated Pd since then that it is probably not the source of the problem as it will have been changed already in later releases.
The fix was made to pd/src/s_audio_alsa.c which is a file that needs to be compiled as the Pd application is built.
If you built your Pd from source then you could change the c file..... change the numbered lines in the link to match the code in the link, and then re-compile Pd.
David.