Environment variable problem on NT Kernel 10 (or above)

Question

When there were accounts A and B, we set JRE as a user environment variable in A and installed a service that requires JRE.

After that, the service changed the logon account of the service to the local service account and confirmed that the service was executed with account B (JRE environment variable not set).

In that case, since it is a user variable, shouldn't the service be executed only in A where the user environment variable is set? Why does this occur?

Used Windows has been identified many times in NT kernel 10 and later (Windows 10, 11, 2016, 2019)

This question can be translated into a translator and have a lot of grammatical errors. Please let me know if you don't understand.