I've been tinkering around with my 11 speed mechanical gravel bike and picked up an LTwoo GR9 (with stabilizer) rear derailleur. Make note there are 2 versions of LTwoo's GR9/GRT rear derailleurs. One with stabilizer and one without. Anyways, I paired it up with Shimano 11 speed Ultegra shifters, Pass Quest 34t chainring, SRAM 12 speed GX chain and ZTTO 9-46t 11 speed XD cassette.

This setup was tailored to tackle the steep mountain trails in my area. Surprisingly it shifts great! LTwoo uses the Shimano 10/11/12 speed road/gravel pull ratio, so everything works perfectly. In fact I would probably opt for this rear derailleur over the 1x GRX 812/822 RD (even if running 12 speed). I prefer Shimano shifters over LTwoo shifters and this Shimano shifter/LTwoo RD combination works much better together in my opinion. 

I've built up my EGR, but I'm running into an issue. Out of the box, it's reading the wrong gear. When I try to calibrate, the process times out — the RD disconnects and fails to calibrate to the correct gear (its on 6th on an 11-speed setup, but reads 4 in the app).

I've tried this on both Android and iOS.

The RD connects and shifts via the app, but during calibration it blinks a green light for an extended period before disconnecting.

Has anyone else run into this issue?

Please don`t get me wrong, you can enjoy and ride your bikes like you want, that is all for your pleasure.

However with the remarks on the ride feel and performance, i think you might admit, it provides a hard time for anyone to take them at face value, when your riding that bike like a city bike. Regarding the round tube profile: The SL8 you mentioned as a comparison has mostly round shapes as well and the fork isn't deep either. Whenever you hear any expert talking about aero, almost nobody will tell you, they could just see how something would perform. I think there is a lot of confirmation bias in claiming to see how aero something is. Again, i'm not saying the slc 3 is as fast as an aero tuned allrounder or aero bike, but i argue, that you are exaggerating the difference quite a bit based on subpar parameters.

I mean that is a fair stance but I have ridden a Tarmac SL 8, just not long term and I own a dedicated aero bike with larger deeper profile tubing, so I can tell there is some difference.  The funny thing about aero positioning is that it's not static.  Yes if I were to ride on the hoods or tops all day, yeah I am pretty upright and have a lot of drag, but in a tucked in position with a 90 degree forearm bend or just riding on the drops gives me all experience I need to know if the bike is "fast" or not.  Maybe I am not an aesthetic queen like some and actually prefer a full stack of spacers since it allows me to be comfortable when I want to, but also allows me to hold an aero position for longer, thus riding further and possibly faster.  Either way, whether it's improper marketing or not, Winspace calls the SLC3 an endurance bike, make that as you will considering the geo is crazy close to even something like a Giant Propel.         

LOL read that again

Please don`t get me wrong, you can enjoy and ride your bikes like you want, that is all for your pleasure.

However with the remarks on the ride feel and performance, i think you might admit, it provides a hard time for anyone to take them at face value, when your riding that bike like a city bike. Regarding the round tube profile: The SL8 you mentioned as a comparison has mostly round shapes as well and the fork isn't deep either. Whenever you hear any expert talking about aero, almost nobody will tell you, they could just see how something would perform. I think there is a lot of confirmation bias in claiming to see how aero something is. Again, i'm not saying the slc 3 is as fast as an aero tuned allrounder or aero bike, but i argue, that you are exaggerating the difference quite a bit based on subpar parameters.