Sharepoint 2016 User Profile Service syncronization only works after iisreset

Question

We're testing a migration from Sharepoint 2010 to 2016 (installed on WIndows Server 2012R2) and we managed to make it work and import all files from old one. We have 2 main problems:

1. Somehow our farmadmin account it's not recognized as admin account in Central Administration and for that it cannot be used to log in (we can only login with a personal account or with any other account but use http://localhost:xxx which only brings part of functionality) - we tried every solution that could find on internet but with no luck.

2. Our User Profile Service not updating user info -> Ex: I have a user in an Active Directory group Alpha and I move it to group Beta -> I try Incremental Synchronization (no update) -> I try Full Sync (again no update) he still can see files from old group and not the new one - only way to see changes is to do an iisreset (or wait for a few hours when something happens and it updates) -> Is this a normal behavior? Because in SP2010 changes could be seen in a matter of minutes or less.

UPDATE - I managed to make sync(second issue) work by doing THIS

$sts = Get-SPSecurityTokenServiceConfig
$sts.FormsTokenLifetime = (New-TimeSpan -minutes 2)
$sts.WindowsTokenLifetime = (New-TimeSpan -minutes 2)
$sts.LogonTokenCacheExpirationWindow = (New-TimeSpan -minutes 1)
$sts.Update()
iisreset /noforce

Answer 1

For your first issue:

Whether the Farm Admin account is added to farm administrators group in CA->Security->Manage the farm administrators group?

If so, try to troubleshoot your issue as below:

1. Switch other farm account to check if the same issue will occur.

2. Remove and re-add the problematical farm account in the farm administrators group.

3. Clear SharePoint configuration cache

4. Re-run the SharePoint 2016 configuration wizard.

5. Run SharePoint Central Administration as administrator and check again.

6. Go to CA site settings->Site permissions->check if the farm account have full control, and check if there is Farm Administrators group in it.