Hi
@lpd777 and thanks for the report!
The Chewbacca event is very difficult, and there is an element of "RNG" (random number generation) or "luck" involved. However, this is an intentional difficulty, meant to reward players for their investment in the Bounty Hunter faction. This is not a bug. If you'd like to provide feedback about the difficulty of the event, then the main forums are the most appropriate place:
https://forums.galaxy-of-heroes.starwars.ea.com/Notes on the event:
There are 10 total Bounty Hunter characters, some of them are more effective at this event than others. Additionally, the number of zeta abilities you have installed and the strength of your mods can greatly impact your success at the event.
A well geared, well zetaed, well-modded group of Bounty Hunters should be able to defeat this event fairly easily. There will always be a certain amount of luck involved - if all the rebels attack the same target and they get several good critical hits and kill 1 of your BHs at the beginning, then you may not recover. However, if your team is consistently failing, then you might need to assess your gear, zetas, mods, and strategy.