I notice that I come across some fills or transitions that just sound bad in the songs I play. They just “don’t sound right.” Tempo thrown off or something.
I don’t have great musical skill or drum knowledge. When I add a song, I mostly copy one already in the list, adjust the tempo, maybe drum kit. If something doesn’t sound right, I’ll change it out in all the songs that have it.
Are there known “clunkers” in there? Is there a list?
“BLUES - fill 6 half bar” is one I suspect is off.
My guess is that behind every beat and fill there is some intent, so in that sense I’d say there are no clunkers 
But some fills do behave weirdly quite often, I think especially if the tempo is too fast 
But I’d guess with the original (slower) tempo they should work just fine 
If I had to guess based on the name the fill is only half bar length So if you are expecting a full bar fill then it will throw you off 
I’m assuming the blues song is in 4/4 so if you can count only 1 and 2 within the fill then its length is half bar Compared to 1-2-3-4 in full bar 
Or with 6/8 half bar would be 1-2-3 Compared to 1-2-3-2-2-3 in full bar 
And I don’t know but you might be able to add 6/8 fill to a 4/4 song and in that case even “full bar” fill would throw you off