Ruger SR1911 standard trigger job question

Bought a new SR1911 2 months ago. Put several hundred thru it & overall was pleased but it needed some smoothing done to the trigger. Trigger measured about 5.5lbs.
Took it to place of purchase, made it clear no after market parts, nothing wild, just smooth up whats in there. Got it back & trigger was 4.5lbs & not much smoother. Shot several hundred more rounds thru it & decided to take it to a well known & highly regarded local smith (yes, should'a done that first)
Local smith shows me the hammer drops when squeezing trigger & moving the safety to fire. We both agree that it should be made safe.

I get the gun back but now, and this is really my question, the first round out of roughly every 3rd magazine, the trigger is extremely hard to pull. I'm guessing around 10'ish lbs or so. Every round in that mag after that is 3.5-4lbs.
Sometimes it'll happen for 3 magazine straight but only the 1st round is heavy.

I've since dropped it back off the last smith I had it at. Naturally I think the first smith I used took to much off something. The 2nd smith, trying to fix what the first guy did maybe compounded the issue?

Either way. Just curious what would cause only the first round in a magazine to have such a heavy pull?

And at this point I'll have the smith return it to factory specs or send it off to Ruger...I'm leaning towards the later at this point.

Got a call this afternoon from the gunsmith. He wasn't able to replicate the trigger issue & even fired a box of 50 thru it without a problem.
At this point I'm stumped as to what was causing such a stiff trigger pull on the first round of a magazine but not every mag.

I'll pick up the gun tomorrow & take it out Saturday, paying closer attention to several things.

Drail said:

Also try to notice when the gun is hard to fire - is the slide is fully in battery?

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This being number one on my list.

I'm also going to drop each round into a check gauge before I head out. I always use them to verify my loads during setup but only check maybe 5-8...all good then I crank away.
I'm wondering if a few were slightly out of spec & not letting things go 100% in battery & just out of shear dumb coincidence were the last in a mag, so it always seemed as if it was the first round.
Most of this 45 brass was shot thru either a g30 or g21, both gen 3's. Never noticed any being bulged but again, something else I'm going to look closer at.

Update. Sorry I didn't get here sooner but I wanted to get a few rounds down it before saying anything.

I'm happy to report the weapon performs flawlessly after 557 rounds. Not once did the trigger bind or hangup as previously reported. Every pull was right at the poundage it should be (about 3.75lb avg)

BBBBill said:

f you pull the trigger and hold it there while you wipe off the safety from safe to fire then the hammer will drop every single time. Nothing abnormal about that.

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Being new to the 1911 I wasn't aware that this was normal operation when I first posted. I think maybe when the gunsmith was showing me the hammer falling I just assumed he was holding the trigger & moving the safety to fire, when in actuality he wasn't holding the trigger.
The smith said, with my permission before hand, fired 50 rounds thru it and wasn't able to reproduce the heavy trigger pull I experienced.
It's like there was a ghost or gremlin in the machine.
Either way he must've torn it down & tweaked or adjusted something. All seems to be right & in proper working order at this point.

I did go back thru my own reloads & case gauged everything on hand as well as plunked them in the barrel. All passed ok.

At this point it's a mystery & I'm not going to jinx it. It's running flawlessly & is a great shooter.
BBBBill, I made a note of the above smith's you mentioned & if in the future something comes up I won't hesitate to contact one of them. Thank you.

Thanks to all that pitched ideas. I appreciate it.