SharePoint showing one hour less in UI in one site collection and correct value in another site collection and both site collections/sites having same regional settings and programmatically it is showing same value in both sites in UTC.
Site1:
Time Zone: (UTC-08:00) Pacific Time (US and Canada),
Date Value UI: 4/7/2021 3:45 AM,
Date Value in Code (UTC): 4/7/2021 10:45 AM
Site2:
Time Zone: (UTC-08:00) Pacific Time (US and Canada),
Date Value UI: 4/7/2021 2:45 AM,
Date Value in Code (UTC): 4/7/2021 10:45 AM
Note: Running CSOM code with GetItemById and checking column value
Full Time Zone Info:
<d:Description>(UTC-08:00) Pacific Time (US and Canada)</d:Description>
<d:Id m:type="Edm.Int32">13</d:Id>
<d:Information m:type="SP.TimeZoneInformation">
<d:Bias m:type="Edm.Int32">480</d:Bias>
<d:DaylightBias m:type="Edm.Int32">-60</d:DaylightBias>
<d:StandardBias m:type="Edm.Int32">0</d:StandardBias>
</d:Information>