HTML Signature not appearing in Replies or Forwards

[Wilsonisme]

I am using Microsoft 365 for Business.

A problem started to occur a few months ago with my outlook. I use an HTML signature which has been fine for years. It appears in new email messages no problem. However, it does not appear in either replies or forwards.

frustratingly, my colleague who works with me has exactly the same settings in her Outlook Options as mine, and yet her HTML signature DOES appear on replies and forwards.

We have the following selected:

• File - Options - Mail - Signatures - select Personal Stationery - in the Theme box is the HTML signature which is saved in the Microsoft - Stationery folder. Nothing is entered in any of the rest of that open page.
• Replies and forwards - We have check / tick marks in the following: Show suggested replies, and Open replies and forwards to a new window

My colleague has also selected in both the 'when replying to a message' and 'when forwarding a message' the option to 'attach original message'. Her outlook does this, attaching the original message (rather than including it) and also with the HTML signature appearing on both. Mine, however, does not show the HTML signature when opting to attach the original message. Also, I change the setting to 'Do not include original message' when 'replying to a message' but I do not have any option to NOT attach or include original message' for forwards. so when I try and forward a message, the original attaches but the HTML signature is not there.

Any ideas on where the settings are messed up please? Or is it likely something has got corrupted at some point? My IT guys have struggled with any solution.

I have my main email account and two others for other organisations I work for on my Outlook. If I deleted them all and then reinstalled Outlook somehow, might this resolve the issue?