Thunderbird sometimes uses wrong "from" address in reply
I'm using Thunderbird 60.9.0 on Windows 7. I have an email account with a number of identities, one of which is set as my default address, which is not the address which I use to login to the mail servers I use. When I send a new message, the default is selected as the "from" address, and when I reply to a message sent to any of the identities, that one is selected, which is correct. However, if I reply to a message sent to an address that is not one of the identities I have configured (most often this will be a message sent by someone else to a mailing list to which I subscribe, and the "to" address will be that of the list server), the "from" address selected is NOT the default, but the one used to login to the servers. This seems incorrect to me; is there any workaround, please, or could it be logged as a bug?
Additional System Details
- User Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:69.0) Gecko/20100101 Firefox/69.0
A little more information: if the "from" address of the message I'm replying to is one of my identities (and the "to" address is not), then the "from" address of the reply is the same as that of the message being replied to. The situation I mentioned happens when neither address is one of my identities.