I use alot of Default stuff myself,never heard of that happening.
Stay away from the offshoots on Fleaybay,I have tried that route and it didn't work out so well.
What were the date codes on the bad ones?
Any chance it was a bad run?
The date codes on what I have here now are all from 2023. I'd guess that the ones I took back were the same.
Bad Run? It happened last fall with a pair of 3ah batteries, purchased separately, and again today with several 4ah units sold as part of a set.
Got one of the latest 4ah units charging now and it looks to be going ok.
I will say that every single battery I used at work was a 5ah unit. What I bought last fall were both 3ah. Todays are 2ah, with no issues, and 4ah with several issues.
