Hi @tictas 1p ,
Please understand our forum is an open platform, in order to protect your personal information, I have deleted your attachment in your post. If you still need post that, it's recommended to post a related screenshoot and hide the personal information via edit your question.
For your issue, what's the specific version of your Outlook desktop client(File>Office account>About Outlook)?
According to my tests on Outlook 365 version 2105(Build 14026.20246), the messages from gmail account through Outlook client could display normally in Outlook. So in order to further confirm your issue and perform more targeted tests on my environment, please provide us with more information about your issues(such as client version and others)
Also, I have researched a lot and found a related article that mentioned similar issues on earlier version of Outlook, if it's your case, please kindly check if those workarounds could be helfpul to you(such as working with "Shift+Enter" instead of "Enter" etc.) (Please Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.)
If your issue has any update, please feel free to post back.
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