Middle layer issue of Prusa MK3S+
I am having a problem with a specific print (it's not a general issue) and a specific layer that is confounding me. It's a circular coffee coaster with a multiple color changes to make the Colorado flag and inevitably on the blue layer (which is the second to last layer), it gets off kilter in the lower left portion of the print which causes issues. I'm really not sure what to even do for troubleshooting as most of my prints come out perfect and have no issues with bed adhesion or any other challenges.
This time I paused the print right after it started the blue layer, and you can see how the top portion of the blue layer is perfect and the lower left portion is starting to get wavy.
Any advice is much appreciated. 
RE: Middle layer issue of Prusa MK3S+
Any advice is much appreciated.
Er, move to somewhere with a simpler flag?
But seriously: This sort of effect often occurs when a part is warping; turn the part over and look for signs of lost adhesion - then try the usual tricks to improve first layer adhesion - thoroughly clean the build-sheet, add a brim, slow down the print - perhaps try printing on a different area of the bed...
Cheerio,
RE:
I think it is even visible in the picture that the print is no longer sticking to the bed near its lower rim. @Diem has already mentioned the usual approaches to try and improve adhesion. On top of that, since you mention that this is a first for you: Is it particularly chilly at the moment? If so -- if your MK3S has an enclosure, maybe try and pre-warm that a bit, or heat the room a bit more.
(If you are looking for MK3S-specific advice, better post in that section of the forum next time. This is the section for the Core One L, which is a rather different beast.)