Hi Matt,
Thanks for your response. Taking each of your questions in turn ...
Is this only from when you are using your phone, does it do this when you use a desktop / other device? Yes it only happens when using my phone, emails sent from laptop are not affected.
Also you have mentioned your phone is Android and you are using outlook, is the app and phone updated to the latest software? Yes, both the phone amd the app are using the latest software, as far as I can tell.
Has this always happened or it just the odd time? This rarely happens, but has done so at least 3 times in the last month for it to be a coincidence.
Could you please try removing the email from outlook and adding it back on. This doesn't appear to improve lmyyertters.
Kind regards