1st cast-catch, then nothing

I fish mainly on two small ponds (#1, 3min. across on 10ft. bass boat
w/ 30lb thrust motor; #2 10 minutes).

90% of the time I fish Senkos , with either 14lb firewire or
spiderwire in the weeds, 8lb powerline in more open water. Pond 1 max
depth is 40 ft, and pond 2 max 15ft. Mostly I'm fishing ofround weeds
and lillies.

Three outings in the past two weeks (twice from 7-11am, and once
around dusk). But the strangest thing is happening. Each outing I've
got a fish (smallie) on the very first cast, or two on the first two,
then nothing for hours. Fore example, today on the dee[er pond, along
the weeds/lillies I had one on the first cast at 4lbs, and the second
one 2.5lbs, twenty minutes later, then nothing for 4 hours though a
few (4) nibbles I couldn't set the hook on.

Just seems like a weired and persistent pattern, or a 6 year amateur
fisherman's day-beginning luck.
Am I doing something wrong? If the Senko's still in excellent shape
should I change it, or the hook, after catching a fish with it? Should
let out line and retie ?

Thanks for any input.

JJR