Understand why com.apple.email.SearchIndexer is mongolizing

[chibenwa]

Closes connection after APPENDLIMIT

Repeats 20 time in a row or more, a few times a day

Something it do not like about APPENDLIMIT?

a1 STATUS INBOX (APPENDLIMIT)
* STATUS "INBOX" (APPENDLIMIT NIL)
a1 OK STATUS completed.

Though it seems okish CF https://datatracker.ietf.org/doc/html/rfc7889#section-3

 The IMAP
   server can publish specific values for each mailbox, and it can
   publish "NIL" for a mailbox to convey that there is no APPENDLIMIT
   for that mailbox. 

Cc @vttranlina it happens on your device.