This issue is resolved in vRealize Log Insight 8.10.2
Workaround:
1. Log into the vSphere Client as administrator
2. Select the vRealize Log Insight node in the inventory
3. Find the rootpw property at Configure -> Settings -> vApp Options -> Properties -> rootpw
4. Perform Shut Down Guest OS on the vRealize Log Insight node
5. DELETE the rootpw vApp property
6. Power On the vRealize Log Insight node
7. Open the console of the node
8. Log into the node with the current root password
Note: If you cannot login to the node with the current password, please use the initial password or reset the password, please see How to reset the root password in VMware Aria Operations for Logs (formerly VMware vRealize Log Insight)
9. SSH to the node as root and run passwd command to change the root password