Review on 🚽 Fluidmaster 504 Long Lasting Flexible Frame Toilet Flapper, Red - 2-Inch Universal, Chlorine Resistant by Paul Beach

Bought three of these a few months ago for future repair/replacement, return window closed just prior to installation. I have used the same damper in my old 3 gallon toilets before and they have worked well. I recently installed a new Fluidmaster flush valve in one of these toilets (it works perfectly) and at the same time replaced the old 1 year old Korky valve which was still fine with no leaks. The new Fluidmaster valve has a slow leak with only occasional dripping. The water loss is enough to activate the flush valve for a few seconds about every half hour. I checked the installation again (was only used with side eyelets, with the tube insert cut off along the marked lines), it doesn't hang or interfere anywhere, the chain doesn't get under it, nothing bad/worn/chips on the bowl's exit seat. After fiddling around for a while I decided to reinstall the 1 year old Korky Flapper which fixed the leak immediately. Upon closer inspection of the new Fluidmaster 504, it turned out that the small circle in the center of the top of the damper was not waterproof and I could easily blow air through it. of course after disinfection. I then opened up one of the other two new ones and found that while it appears to be waterproof, the same area on it is rough and very thin. They can most likely be repaired with a good quality silicone, but that's obviously not necessary. I wonder how many of these poor, downtrodden crackers have escaped from a lumbering Chinese factory with the same defect, but I'm hearing this is another case of pi field rioting. I haven't had a toilet valve brand choice before, but if they don't report back and get it right I will avoid Fluidmaster in the future and recommend others to do the same. Happy to reconsider if they offer an appropriate answer.