[Bug] Upon refreshing/loading new emails older ones disappear instead of loading the new ones

When refreshing/loading new emails, instead of adding the new emails to the list of emails, it makes the older (newest before refreshing) disappear.
Upon inspection I can see that it hides the exact number of newly received emails (1 new mail, 1 top mail gets hidden, 3 new mails, 3 top mails get hidden), I used to get around this by refreshing mails while in the “Inbox” category and when I saw mails disappear I switched to “Unified Inbox” where I could see all the newly loaded mail, but in case of “Sent Mail” for example this completely screws me over because I can’t just see newly loaded ones no matter what.

As far as I understand it I would say it is expected behavior. At least for IMAP you have a setting at Settings / account / Fetching Mails / Local folder size. For me it is set to 100.
If you have reached that number of mails in the folder and fetch X new mails then X old mails should vanish from the folder.
In case for POP3 I have no idea if there is a similar setting.

Problem is, the new emails do not appear on top visually, instead the newest ones that were on top before refreshing disappear (instead of the oldest ones getting deleted) and then the newly fetched emails just do not appear.

If this is hard to understand I can try to screen record to show it off