As long as it can connect intermittently, NTP should occasionally sync, so your time will be ok, and timers should work normally. Try this:
on wifi#disconnected do timer1 1 endon
or on wifi#disconnected do timers 0 endon
if you need to evaluate time of day when wifi disconnects so you can activate relays, you can use events like so:
rule1
on wifi#disconnected do rule2 1 endon
on wifi#connected do rule2 0 endon
rule2
on time#minute do event t1=%value% endon
on event#t1==630 do var2 3 (or power1 1, or whatever) endon
on event#t1==1233 do power3 0 endon
That way the triggers only activate when wifi is disconnected, so MQTT messages are no longer controlling your relays.