agree with the above posters who suggested taking them back. i've had the same issue with other shimano's and returned them. it's not worth trying to figure out an intermittent problem on a brand new reel.
1 of my favorite reels for trout fishing that's still available for sale is the Pflueger Supreme 25. It's got a 1000 size body, but it only weighs 6.6 oz. line winding isn't perfect, but it's pretty good. you might need to pilfer some spool shims from another reel to get the line lay perfect when you 1st spool up. that part might take a couple tries. after the initial start-up, it's a great reel for trout fishing. smooth (much smoother than president or president xt), casts further than a 500-size spool, light-weight, great drag. the new ones have a slower gear oscillation which improves line lay over the previous models.
if you want to go old school, the Daiwa SS700 is hard to beat. weighs 7 oz. excellent distance and drag, but sloppy anti-reverse. worm gear oscillation gives perfect 5-degree cross wraps. i forget where they make them now (thailand?). if you can find an older one made in Japan - that would be my preference. the reel design hasn't changed in 30+(?) years. i love mine and i've fished it hard for the past 30 years and it's still in good condition. i primarily use mine for casting spoons directly into the wind on 4 lb test for trout.
if you can find a symetre 500fj on ebay or something that would be my 3rd choice. i use that 1 with straight 2 lb maxima ultragreen mono for fussy trout & tiny plastics on jigheads.
good luck with the trout!
I bought a Shimano Sedona 500FD a couple months ago and on the first or second time out it started to feel like it was sticking/binding... the handle felt stuck. I set it down and fished another as I always take two. Later I picked it up and turned off the anti reverse and worked the reel back and forth. It seemed fine. 
