Hi jquertin,
As Aleks correctly pointed out, it’s better not to use DIIS (which is active by default) when using SPINLOCK.
A good way to combine the two is like this:
This way, DIIS is only activated when SPINLOCK is turned off.
However, I tried running your input, and it’s likely that this is actually a bug. Unfortunately, I don’t have a better solution at the moment other than changing the functional.