Steps to reproduce (non-utc timezone in interface):

1. Block a user using Special:Block with a given expiration date and time by text input (2019-11-24T10:00:00 in "other time" input field when the pen icon is active)
2. Block a user using Special:Block with a given expiration date and time by using the date and time picker (calendar icon is active, same expiry as in step 1)

Expected behaviour:

• the two blocks will end by the same time and by the exact time in the current timezone specified in the inputs

Actual behaviour:

1. Block #1 will end at 2019-11-24T10:00:00 in the local timezone
2. Block #2 will end at 2019-11-24T10:00:00 in utc (in Germany currently 2019-11-24T11:00:00

Example:
https://de.wikipedia.org/w/index.php?title=Spezial:Logbuch/block&page=Benutzer%3AInkowik-II

• the first block has been made using the text input and resulted in the expected behaviour
• the second block has been made using the picker and resulted in the unexpected behaviour
• the expiration time typed in the fields was the same

Solution:

• At least, the two possibilities to specify an exact expiration time of a block should lead to the same resulting block expiry.