To be clear, world-wide there are no issues that have been discovered with the 2018 battery.
What has been discovered is that 97% of those that have a 2018 don't have a driving regime that requires multiple daily quick charges, and those that do, are able to complete their quick charge successfully.
The safety and longevity safeguards built into the LEAF operate as designed using the same method that ALL other BEVs quick charge systems employ, namely the throttling of the charge level to mitigate heat degradation. The result of that is that it may take a little longer to complete a quick charge session. It does not matter if you quick charge a LEAF, Bolt, Tesla or VW, all of these BEVs employ throttling of the charge to promote battery longevity, which will vary the time that a quick charge session lasts. Depending on the variables that occurs during your Quick Charge session "Your quick charge session time may vary."
Some find that intolerable, but then again, if there weren't safety systems to protect the longevity of the battery, those same outraged complainers would find that intolerable as well.
2018 LEAF SL
Delivery April 10 2018
2014 LEAF SV
Delivery May 23 2014
50,000+ miles - all 12 bars - Same range as new - No warranty issues ever!