Sent items from Outlook App (iOS) not syncing with IMAP mail server

Exact same issue, using Outlook on an Ipad, and Btinternet IMAP email.   But only noticed the problem since my Ipad updated to iPadOS 14.2 a few days ago

Exactly the same issue. This is both on I-pad and i-phone. I contacted the technical support, but no help. I re-loaded the latest versions of the Outlook  apps. Cleaned up e-mails. Nothing helped. Looking at the number of replies and views this must be a major issue.

i contacted technical support several times without success, besides advice to download the latest outlook version.

more than 600 views. This looks to be a Microsoft issue. They need to be transparent with us, that this is an issue they are working on or not.

Andre are you connecting to an Exchange server? If so what version please. I ask because as far as I can tell this started after updating Exchange 2013 to CU21 patch.

I can access all folders and even access messages sent from my desktop for example (synched immeadiatly), but outlook will not automatically assign any of the IMAP Folders to actions it performs such sent emails, deleted emails, drafts. Only action that you can assign a folder on ios is “Archive” which for the first time you use it, asks where would you like to move the message to. If you send an email, it warns you that the message wont be saved on any folder and asks if you want to send it anyway. If you try to delete a message (originally it would move the message to trash folder), it will jist ask tou if you want to permanently delete the message (erase rather than move fo trash). Its anoying since it worked beatifuly before, but stopped without any tampering with settings. I wonder if this is a bug after an update or so. I want to be able to assign folders again.

I have sent items on my phone that does not appear on my sent items in Outlook in desktop. I tried to look for configuration for sent items in the app, same thing with the desktop where you can set Outlook to save sent items, but I couldn't find any.

I did notice the sent folder is there.  It is weird.  So, I downloaded the Outlook iPhone app and logged in manually by adding my work email through IMAP.  I do have an original Outlook live account but didn't sign in with that.  When I clicked on calendars and added my personal Outlook live calendar by typing in my real Outlook live account it synced fine.  The sent folder was there for that and I found my work (IMAP) sent items in there as well as my personal Outlook live emails.  I suspect there is a major bug somewhere.  SO...I would create an Outlook account (personal).  Use IMAP work to sign in to the phone app and enter it manually through IMAP page, then once you have that, add your personal calendar using your personal Outlook acct.  I tried to support and they never got me an answer which was frustrating.  Then when you send and email you have to send it through your personal but make sure the "from" is your work email address or your clients will see your personal.  CONFUSING!  But it seems to be a work around for now.