@bmercier I also have the same results as @sjenkins after upgrading to 5.9.1_21 and rebooting.
The rest command gives this, which seems normal:
{"timestamp":"2025-06-07T08:26:11.581210-07:00","families":[{"id":"1","name":"","instances":[{"id":"1","name":"","nodedefs":[{"id":"RelayLampSwitch_ADV","nls":"147","properties":[{"id":"ST","editor":"I_OL_RELAY","name":"Status"},{"id":"ERR","editor":"I_ERR","hide":true,"name":"Responding"}],"cmds":{"sends":[{"id":"DON","name":"On"},{"id":"DOF","name":"Off"},{"id":"DFOF","name":"Fast Off"},{"id":"DFON","name":"Fast On"},{"id":"FDUP","name":"Fade Up"},{"id":"FDDOWN","name":"Fade Down"},{"id":"FDSTOP","name":"Fade Stop"}],"accepts":[{"id":"DON","name":"On","parameters":[{"id":"","editor":"I_0_100_PERCENT","optional":true}]},{"id":"DOF","name":"Off"},{"id":"DFOF","name":"Fast Off"},{"id":"DFON","name":"Fast On"},{"id":"QUERY","name":"Query"},{"id":"BEEP","name":"Beep","format":"/level/${c}/${c} ${v}/","parameters":[{"id":"","editor":"I_BEEP_255","optional":true}]},{"id":"BL","name":"Backlight","parameters":[{"id":"","editor":"I_BL"}]},{"id":"WDU","name":"Write Changes"}]},"links":{"ctl":["I_CTL_DIMMER_ADV"],"rsp":["I_RELAY","I_RELAY_ADV"]}}]}]}]}
Still receiving "Error loading node 2A 43 78 1: Profiles loaded but nodedefs missing", same on all Insteon nodes