Flipper Assembly replacement - 1 or both - poll

You don't need to change the entire flipper assembly. Did you change the coil stop first? That has been one problem that Stern has had recently with POS coil stops that cause sticky flippers...a $4 part. But whatever you do to one side ALWAYS do to the other side. Always. Well, except changing the entire assembly. I wouldn't be doing that.

When flippers Stick it's nearly always a binding issue, sometimes that's as simple as adjusting the height of the flipper bat, usually best to rebuild

And I think most will agree if you do one, do both(all)
Like when you do your brakes

The Stern stops come apart where they're peened to the bracket. It causes the flipper to get sticky.

Other things to check, dirty coil sleeve, bad plunger/link and not enough up/down play between the bat and bushing.

This is often unnecessary on newer Stern Machines as the coil stop is the weakest link as the brass rivet on the coil stop often times break before there is any wear on either the coil stop itself or the plunger.

Unfortunately this is not even guaranteed with a new flipper mechanism in a new Stern machine; I've replaced broken coil stops in machines that were less than a year old.

Baby with the bath water advices.

I have no doubt you are very experienced here, unfortunately your experience is working against you as the the most common flipper related problem on newer Sterns (Spike and later SAM) is that the coil stops actually break with zero wear to the actual stop itself or to the plunger. Now I do replace the coil sleeve as well since there is no reason not to; and I never replace the EOS switch on these newer machines (unless its physically broken) as there is just no reason to.

I'm sure there will be a time that an entire flipper rebuild will be needed; granted I don't know for sure that the OP's HUO machine doesn't have a worn plunger, but I'm willing to bet it doesn't...I'd also be willing to bet there is a small pile of brass dust in the bottom of the cabinet under the flipper that's having an issue.

Can we hear more aboot how long you've been fixing machines?
So...fucking...interesting

My personal experience on newer Sterns has been simply the coil stop going bad (falling apart) on the flipper assembly. We had a Munsters less than a month old and the coil stop had fallen apart. Tell-tale brass dust on the bottom of the cabinet was the giveaway signs of a bad stop.

We use replacement coil stops from Pinball Life now.

it seems Pinball Life is buying their coil stops from a different source than Stern (and likely some other major parts retailers.) anecdotal evidence says that the PBL stops last a lot longer than the originals.

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on the original topic, i've found that after two or three years of solid use the plastic links on Stern flipper assemblies tend to oval out and cause a lot of slop and loss of power. if you don't mind spending the time, the linkages are pretty easy to get parts for and can be repaired for a lot less than a full kit or even new linkage will cost you. generally though, if one is sloppy like this chances are good the other one is too and you might as well repair or replace both.