Happened to me as well. I think, it might be a punishment for playing to much, since I picked up my level of activity on Stars quite a bit recently. Or maybe its a punishment for winning to much, since my winrate has also been high during COVID-19. Its essentially a reverse loyalty program, since they want to focus on recreational players rather than winning regulars.
Its not great obviously, but currently the full ring cash games on Stars are to good for me to really worry about reward programs or lack thereof. So I just accept, that I win money from the fish, and that Stars keep 99% of the rake, I pay to them. And I am not completely livid about this policy. If more generous rewards make the fish redeposit, when they are broke, that also benefit me in the long run.
And who really needs those chests anyway? My last one contained 40 star coins, which is 0,4$ and then a 1,1$ tournament ticket, which I can only use for the MicroMillions event. And since I currently play 25NL cash, its almost not even worth my time to use that ticket.