No filter on our pump either, which I found odd when I first discovered it.
On the 2350, the water pump is located under the bed and to access it you have to take the mattress off the bed and remove a lot of screws holding two large and very heavy pieces of chip board to the the bed framing. You can also see the pump and use a winterizing hook up vinyl hose through an access panel at the back of the outside storage compartment. I think (??) I reported on this forum that a couple of years ago my pump quit working while we were boondocking. The reason was that the head of the pump was attached to the motor with some long 1/8th inch or so fine thread screws which screwed into the crummy metal covering for the pump end of the apparatus. They had become loose and wallowed out the threads in the too soft metal of the pump.
Luckily, in a town of about 500 people not too far away, I found a kind of general hardware/auto parts store that actually kept a few rv supplies.........including a small rv water pump. It cost me exactly twice the price on Amazon, but I wasn't arguing, bought it, pulled the bed apart and replaced the original. I think I posted on this forum back then advising folks to check the bolts on their pumps to make sure the same thing wasn't happening. I have no idea what caused all those screws to wallow like that but they were beyond tightening.
I noticed also that the water pump was hooked directly to hard (PEX) piping without using a flex hose. That, of course, transmits vibration into the pipes and further stresses the system.
So, again, we might want to keep an eye on our water pumps for loose screws and .....now....the reported plastic debris. By the way, I drilled thru the wallowed out threads and used a larger diameter screws and nylon nuts and now carry the old pump for a spare.