[Adam Gottfried]

I will answer, in case anyone finds this thread and feels as frustrated as i did before I figured this out. If Resolve suddenly stops cutting both the audio and video for clips (even though they are linked and *should* cut together) you should check to make sure that the chain-link icon, directly above your timeline, between the magnet icon and the suitcase with two-way arrow, is selected. This fixed the issue for me.