TB 138 no longer handles multiple CalDav accounts with (baikal) server

We've been using Thunderbird on Windows for quite some time to sync multiple calendars and address books with our baïkal CalDav server. Recently (since 138?) Thunderbird is failing to handle multiple calendar accounts. Anonymized description of the situation: * Let's say that our baïkal caldav server resides at https://abc.com * There are two user accounts at this baïkal server: user1@abc.com and user2@def.org (Notice that these two users have different domain names and tld's) * Of late, only the first caldav account (user1@abc.com) is handled. The second caldav account (user2@def.org) ran out of sync. * On the mobile phones, using davx5, all calendar accounts sync perfectly. So nothing is off with the baïkal server. * After removing the calendar(s) associated with user2@def.org from Thunderbird, it is not possible to add these again. After entering the e-mail address (user2@def.org) and the correct url of the caldav server, it looks like the user is overriden by user1@abc.com. There is also no dialogue asking for the password of user2@def.org. My guesses: * Either TB 138 - silently - insists in caldav user accounts having the same domain.tld as the server * Or TB 138 somehow overrides/overwrites an alternative e-mail address with the one already present, hence the missing password dialogue Anyone else experiencing this?