Looks like I forgot to disable modifiers when switching between profiles of the same verb, this is to fix that. I discovered the issue shortly after my code got merged, with a weird UCM config that caused a segfault when switching profiles.
For example, when we have a Speaker-Mic conflict and a PlayTone modifier with a PlaybackPCM value that has SupportedDevice of just Speaker. This gives us two profiles: Speaker (with PlayTone as another mapping), and Mic (without). When switching from Speaker to Mic we get a segfault because we try to disable PlayTone's map->ucm_context.ucm_device which is null.