I have observed repeated freezes when trying to use Resume Playback (via both the main menu and the Play/Pause button) immediately after relaunching the current dev build 4a6b27a712-250221 on two different iPod mini 2nd Gens (both of which are set up more or less identically to each other). This only happens following a relaunch, not after reboot or shutdown. It doesn't happen at all when running my most recent backup dev builds on those two minis from which I updated today - one of those backups is 7897cded2d-250218 and the other is ee4591d9e7-250216. It also does not happen at all with 4a6b27a712-250221 on an ipod6g, an ipodcolor, and an ipod4g that I tested.
I discovered this because I was modifying cabbiev2.wps on one of the minis and then using relaunch to test that mod. So after testing that mini for the freeze several times and consistently having it happen, I updated the second mini and observed the same freezes. Although my mod to cabbiev2.wps was working properly, I temporarily reverted it back to the standard issue version of that file to make sure my mod hadn't caused the problem. In fact, I observed the freeze immediately after relaunching the dev build update on the second mini, while its copy of cabbiev2.wps was still pristine/original. I had done that dev build update with Rockbox Utility while the mini was booted into Rockbox and connected via USB. So after disconnecting, Rockbox asked me if I wanted to reload/relaunch (I can't remember the exact terminology it uses) and I clicked Yes, at which point it did the relaunch, not a reboot, and I got the freeze when I tried to Resume Playback. I tried numerous times, varying between relaunch and reboot, and it consistently froze every time with relaunch but never with reboot. Also, to be clear, I only updated Rockbox once on each mini, and then repeatedly tried relaunching - I did not repeatedly update and relaunch, update and relaunch, etc. And it does not happen if I select something other than the current playlist to play rather than Resume Playback.