[exim] Exim, OAUTH2 and gnutls problem

Hello,

This is my first post to this list. This is partly to report that I have
OAuth2 working with office 365 smtp servers, but mainly to ask for help
in diagnosing a TLS error which I think is probably unrelated.

I would have posted to one of the existing threads, but the archive
"reply" button does not work, and I do not know how to join a thread
only active before I subscribed to the list.

I am using a somewhat adapted exim.conf.template using debian testing.

While testing, I have encountered two apparently benign error messages:

1) H=outlook.xx.office365.com [xx.xx.xxx.xxx] TLS error on connection (recv):
Error in the pull function.

That was after a succesful delivery using XOAUTH2 to the ms SMTP server.
At first I thought that it might be some quirk of the MS XOAUTH
implementation.
But the I discovered somewhat similar report during a delivery to an "ordinary",
smarthost:

2) H=mail.xx.xxinternet.com [xxx.xxx.xx.x] TLS error on connection (recv): The TLS connection was non-properly terminated.

I am using the debian light binary, and have gathered some debugging
information using the -dall+tls+auth+transport+timestamp option.
A trimmed and redacted version is attached (as a gzipped text file): I hope
this list allows attachments..

That report of an otherwise successful OAUTH2 delivery to the office365
server shows that the error is coming from gnutls_record_recv:
"14:53:07 tls_read: err from gnutls_record_recv"

It appears to be harmless, but I am no expert on TLS, so I am seeking
any help or comments. I plan to upload my script (shell + gawk) to
Gitlab, but want to sort out this error first, although, as I say, I
suspect that it is unrelated.

ael