"Can you go through this hours-long process to reproduce an issue i saw and debug it? I don't have bandwidth."

"Sure, but I'm pretty sure the issue is actually due to your recent changes in [related feature], and I'm pretty busy myself."

"No, that's not how that works. Please figure out the real issue." (Strongly implying it was my fault)

*Goes through hours-long process to reproduce* (yes this procedure could be improved but this is a rant not a planning meeting)

*Of course, it was his change*

"Oh. Well, it's not really a priority."