But this is why lithium ion batteries need special lithium ion charging circuitry in the first place... If you don't have this, the cells will happily take as much energy as you give them and then promptly catch fire.
It doesn't make sense to me that this would only now be a problem. Either the circuit was designed correctly, and this excuse is bullshit, or they should have issued a recall ten years ago.
You are probably thinking of NiCad and to some extent NiMH simple constant current chargers. If you do that with a lithium battery you will have problems pretty much right away, possibly involving fire.
