Nick and I worked out a fix this morning – currently the module’s +/-5V LDOs power up simultaneously after the +5.5V rail goes online. By changing the -5V to be enabled only after the +5V is good, it appears to have resolved the startup issue. The rework involves a simple trace cut + rework wire installation – not really possible to do on the user side, and needs an experienced SMT technician.
There’s a recall callout here, so you can send in your modules to get the correction: