save() on espruino_1v91.122_esp8266 results in immediate Disconnected prompt

I noticed these very similar issues in a separate forum topic thread

but primarily with the puck. Could changes then (a month ago) now have an effect on the existing firmware? I only bring this up as @Robin 1v84 and @Ollie 1v87 commented on stable save() use after flash, yet right around 1v90 a month ago, a few have had similar disconnect issues after save() doing different tasks on separate development environments.

18 stevie4711 1v90.09 ". . . . But I got the disconnect on save()"
19 dklinkman 1v90.12 "Same here. I get the disconnects on save periodically"
20 stevie4711 "The more you use save() the more often it happens"
21 dklinkman 1v90.12 "If I try the puck disconnects."
30 Joakim 1v91 " . . . but disconnections on save() and . . . "
32 Adam79 " . . . and trying to save the code getting disconnects."
38 Gordon "and save() which worked fine before is now broken."