Hello. I have a Frigidaire PLD2850RDC1 dishwasher, and after running a cleaning cycle, I've found specks stuck on several of my dishes (presumably leftover food from other dishes). I did some research that suggested cleaning the trap (part AP3773597) could help remedy this problem. When I went to do that, I noticed two issues: 1). The trap and other related parts were not being held in place because one of the two "tabs" at the top of the Volute Cover (part AP2109083) had somehow melted, so I need to replace that part and 2). I found a separate piece at the bottom of the tub that I can't identify from the diagrams of my dishwasher or the parts list. It's a small, white, circular piece that has two clips at the bottom of it. The only writing on it says >POM<. I have attached two pictures of it. I'm not sure if this is a standalone part or if it's a piece of another part. Do you have any idea what part this might be?

Thanks in advance for your help.