Factory reset without erasing data will cause second user data removed?
I went ahead tried to factory reset my phone without erasing internal storage.
Device - Oneplus 5, Android 8.1.0 , OOS 5.1.4, Not rooted
Before reset
Users

admin
work

Below are the storage details
admin       - /mnt/user/0
/storage/emulated/0
work        - /mnt/user/11,
/storage/emulated/11
guest mode  - /mnt/user/10,
/storage/emulated/10
After reset, names of users are reset and only default user name is seen which is Device Owner
Users

Device Owner

Below are the storage details
Device Owner  - /mnt/user/0 ,
/storage/emulated/0
Files in /storage/emulated/0 are not deleted. All files of second user got deleted. Looks like it completely wipes second user in this case. Guest user got deleted too.