Did you put any sealant on the push rod tubes before the seals where put on them ?
Have seen a lot of those seals slide over the ring on the tube and than burst because some sealant was used there.
Just thinking why they would burst.
Of course there could be some bad ones out there.
BMW R100'91/R80'93/R75/6 R80ST'83/R65GS'87/GasGasTXT300/DouglasW20-1920