Our team has been notified of such crashing issues, thank you for reporting.
We'll be monitoring and investigating such cases and if you come across this situation, we would appreciate it if players can provide us with the following information via Forum comment/Discord DM or Customer Support ticket.
1. Screenshot (if feasible before the crash)
2. World, Channel, Map name, and Time (with timezone specified)
Christougher is correct, we've confirmed with the team that the increased delay for Thunderbolt is intended.
However, we're well aware of the sentiment towards this change and understood how much it affects smooth gameplay for the class.
We'll be reviewing and relaying the feedback concerning this skill change to the team, thank you.