LTHR auto-detection, maybe some sanity check should be added?

Maybe just switch to another watch(looking at the history and amount of posts you made). If Garmin watch is not suitable for you, why take the pain of using it?

That sounds so stupid fanboy comment that oh c'mon.

Unfortunately I don't know better watch, but it doesn't mean that Garmin gets everything right.
Maybe you should recommend one then? And have good reasoning why it would be better if you really want to suggest that.

Looking your one comment before that you commented on a post that reported issue and it was then fixed. How's like this any different from that? I would think that it would be pretty smart have some constraints for what the LTHR detection value should be. Unfortunately I'm not expecting Garmin to take really ideas from here, but posting to the Share Idea's is just a black box, so others can like share their experiences, does LHTR work for them or not.

Sorry but if the issues exist, then Garmin is either not aware or hasn’t prioritized them. Garmin created this forum for a reason - as a way for us to let them and other users know of the issues we are experiencing. 

So either you also face a similar issue (greater numbers = greater priority to Garmin) or you know of a fix that can help the user who posted.

Are you using external HR sensor?
How long are you using this watch?
From my experience LTHR and HR Max detection works fine.

External HR, Garmin HRM-Pro Plus. Over a year. My experience is that max hr is not good and now also LHTR gave pretty joke result. 

Also the HRM-Pro Plus is pretty new, had some doubts on previous one numbers so did get a new one. Bought from August 2024. 

I'm also using MRM-Pro PLUS and at the beginning of the year I started to get weird HRMax and LTHR results but it was rather because I had over two months break in trainings.
After couple weeks it stabilized and numbers are similar to what I had earlier.
I'm using HRM-PRO Plus since 2023, previously I had HRM-Pro and earlier HRM-Run.

I think you have a misunderstanding about lactate threshold heart rate (LTHR). It's not a single precise number. With real blood lactate testing you are essentially looking for an inflection point on a chart with a small number of data points, so you have to rely on interpolation and curve fitting. Even the best test in a sports medicine lab test will produce an approximate number with some error range. This number can change a little from day to day based on your fatigue level, time of day, the technician performing the test, whether it's on a treadmill versus stationary bike, etc. LTHR can be a useful guide for calibrating training zones but don't rely on it too heavily.

A fitness tracker device obviously can't directly measure blood lactate level so it has to rely on other indirect metrics like pace, power, heart rate, heart rate variability, and respiration rate. With enough data the device can estimate LTHR but there is some variation between individuals and it's impossible to be really exact. Users who don't understand the difference between precision versus accuracy might be confused by this.

I think you have not read the post? I find it highly unlikely that LTHR would be so close to max HR.

And yes, optical or electronical HR can not measure lactates, but here we are. They have this thing. I think it should have some sanity checks when it thinks have detected something. 

I had read your post. The device can only accurately detect your max heart rate if you actually do a maximum effort activity like a ramp test. Have you done that lately?