One printer is suddenly having problems with top layers/bridging

[roykirk]

I have four of the exact same printer model (Flash Forge Creator Pro), all using the same brand/color of PLA and all printing from the same batch of models. Recently one of the printers has developed a problem with printing the final few layers of a model and/or any sort of bridging. Parts with bridging typically fail at the bridge (although not always). Other times parts of the top layer will have imperfections or gaps, sort of like the filament stopped feeding in certain sections.

I've tried changing out the filament roll (in case it was simply defective), cleaning the nozzle and changing the teflon feed tube. I've looked at the belts, double checked print bed leveling, etc. I simply can't figure out why this one printer is suddenly having problems that none of my other printers are suffering from. Does anyone else see something I should be checking that I'm not thinking of?

[curious aardvark]

what does the rest of the print look like ?

bridging nis basically just normal extrusion - usually slightly slower (I generally run it at the same speed as the rest of the print)
So if you've got under extrusion it really should show in the rest of the print.

[roykirk]

what does the rest of the print look like ?

bridging nis basically just normal extrusion - usually slightly slower (I generally run it at the same speed as the rest of the print)
So if you've got under extrusion it really should show in the rest of the print.

The rest of the print looks fine to the eye, that's what's weird to me. I will say that around any straight edges on the top layers of the print, there will often be sections where the filament didn't adhere fully to the layer right next to it.