Normal
A solid plastic shim yes... Plastic under a joint will loosen no matter what you try ro do with it... Its a fact... Dont matter if you say yours never loosened up... You might not have used it enough to notice it... I guess we can talk about this all day but, with 5 years of fastener testing at Ford I know what it will do... Ive tested hundereds of joints with plastic under it. If the joint will bear a load it will get loose... and hey, have a greatholiday !!! Dont ya love the FRF... to be able to talk and not have a ******* admin jump in and say ok guys lets cool it!!!