Outlook 365 on Windows 10 erases typing when Enter key is pressed.

All of a sudden, when the user is typing the body of a message in Outlook for Office 365, pressing the Enter key deletes everything that has been typed.  I tried a Quick Repair, which didn't help.  I didn't do a full repair - that takes too long, and in the past the full repair doesn't do much.

Even if I plug in a wired keyboard, the text still disappears.
This doesn't happen with Microsoft Word

I tried typing with a different font.  Message still disappeared.

Is there a solution besides a complete uninstall of Office 365?

Thanks.

OS Name   Microsoft Windows 10 Pro
Version   10.0.19042 Build 19042
Other OS Description    Not Available
OS Manufacturer   Microsoft Corporation
System Name   BARBARA-PERLMUT
System Manufacturer   Dell Inc.
System Model   OptiPlex 5480 AIO
System Type   x64-based PC
System SKU   0988
Processor   Intel(R) Core(TM) i7-10700T CPU @ 2.00GHz, 1992 Mhz, 8 Core(s), 16 Logical Processor(s)
BIOS Version/Date   Dell Inc. 1.4.1, 11/4/2020
SMBIOS Version   3.2
Embedded Controller Version   255.255
BIOS Mode   UEFI
BaseBoard Manufacturer   Dell Inc.
BaseBoard Product   05T2V2
BaseBoard Version   A00
Platform Role   Desktop
Secure Boot State   On
PCR7 Configuration   Elevation Required to View
Windows Directory   C:\Windows
System Directory   C:\Windows\system32
Boot Device   \Device\HarddiskVolume2
Locale   United States
Hardware Abstraction Layer   Version = "10.0.19041.906"
User Name   BARBARA-PC\Barbara
Time Zone   Eastern Daylight Time
Installed Physical Memory (RAM)   16.0 GB
Total Physical Memory   15.7 GB
Available Physical Memory   9.40 GB
Total Virtual Memory   20.2 GB
Available Virtual Memory   13.1 GB
Page File Space   4.50 GB
Page File   C:\pagefile.sys
Kernel DMA Protection   Off
Virtualization-based security   Not enabled
Device Encryption Support   Elevation Required to View
Hyper-V - VM Monitor Mode Extensions   Yes
Hyper-V - Second Level Address Translation Extensions   Yes
Hyper-V - Virtualization Enabled in Firmware   Yes
Hyper-V - Data Execution Protection   Yes