Pre-Hotspot dst-nat gets lost sometimes.

Guys, I made a dst-nat in the chain PRE-HOTSPOT, where I redirect all udp/tcp of port 53 to my linux server.

Works fine, but sometimes happens something with the hotspot that stops to work. I know that the problem is on the hotspot, because other in the network using the linux bind9 are not affects, just the hotspot ones. Looks like something gets lost after few days and dont get back.

When that happens I need to disable the dstnat rule and let the DNS of my Mikrotik respont to the dns queries.

what am I doing wrong ? is this the correct way to point a dns redirection to the hotspot users ?

cheers