I'm sure it's a MS thing, or perhaps it's an ethanol thing (i.e burns faster in a hot chamber vs. cold?).
But basically ,on a cold start, it cranks over normally, fires and starts. With a hot/warm engine, it cranks over for a half second (I assume while it's getting the tooth counting thing going - I'm using a DSM CAS so it has to pass #1 TDC), then as it tries to start it pushes back against the starter. No popping, the cranking speed just gets lurched back to damn near zero, then the starter recovers and cranks it forward again until the next cylinder fire, which does the same.
It not using the ignition maps at that point (IIRC). I'm thinking I just have the cranking timing set a bit too advanced. Works when cold, not when hot when presumably the ethanol fires off more quickly (???). I know there is a coolant temperature based 'cold engine ign advance' feature. I probably need a bit more of that and a bit less 'normal' cranking degrees.
If the battery was feeling a bit peppier it could just power through those push backs and the motor would start, but it's small, it's old (ish), and it's weak, so it just seems to sap it pretty much when it tries.