The issue that you describe might have to with the M32' pitch/gate handling, as described by catwavez and Lugia above this post. However it can also be that you need to adjust rings a bit.
I understand that you've got this module cause it sounds amazing, BUT rings is known to be hard to tune in scale because both the frequency (input labeled as v/oct on the panel) and shape are both influencing the pitch. So let's say you've tuned your rings with the frequency knob and you are changing the shape, it could go out of tune again.
My suggestion would be to set up your rings as described in Lightbath's guide: https://lightbath.zone/tune-rings . This way, you have a clear 'starting point' from which you can work out what the issue is. Try to see if Rings sounds acceptable in this way by plugging and unplugging a cable in and out of the "strum" input, thus triggering the sound.
Check the Beatstep's CV/gate settings by hooking it up to your computer and opening the MIDI Control Center software (free download from the Arturia site). The BSP manual provides extra info for this in chapter 10.9.6. called "CV/Gate mode". For controlling Rings, the gate mode of the sequence you want to use (seq1 or seq2) needs to be set to V-trig I believe. Pitch mode needs to be set to v/oct and you can experiment with the seq's 0V midi note settings. Try to see what happens if you set this to C1, C2, C3 or C4.
If you want to keep controlling the Mother-32 with the BSP as well, I'd suggest to keep using the selected seq that it works with now, and change the settings of the other seq to match with Rings.
Good luck!