Your first boss will forget your name. Your work ethic will follow you anyway.

The specific job disappears from memory faster than you would expect, on both sides of it. What stays is the habit you built while you were there: whether you showed up, whether you did the part nobody watched, how you were on a bad night. That pattern walks into every room afterward, because it stopped being about the job a long time ago.

Treat the current unimportant thing as practice for the important one. Do the shift properly even though it is temporary. You are building the person who arrives at the next place more than a reputation with this manager.