My iPhone X has this too... a very narrow pink hue on the left hand side. It gets less noticeable as the brightness goes up, but I notice it whenever I am reading at night with the brightness low (and especially when Night Shift kicks in). It's not something I looked for, I noticed it while reading email and in the News app when I first got the phone.
I went to an Apple Store here in Manhattan and compared my X next to a few that were on display and here's what I found... After setting all phones to full brightness, turned off True Tone and Display Accommodations, I noticed that all the phones that had this slight pink hue towards the left appeared to be a bit brighter, had more contrast, and had better whites than the phones that didn't have this issue.
The other phones had this awful green/blue/yellow tinge to them, so I decided that I'd rather have a brighter more vibrant looking display than a greenish tinted one. I even set the Display Accommodations on green/yellow tinted phones to see if that would correct them, and while they looked a bit better, they were still dull and dingy looking compared to mine. My display downright pops when I have my preferred Display Accommodations set.
I also noticed that the pink hue varied from phone to phone on the display models, and mine is clearly not as bad as the ones I compared them to. Also, I noticed that mine was a bit brighter and had better whites, so again, I am not sure if I want to start playing the lottery. If I get one of those blue/green/yellow tinted phones, I'd have to keep swapping.
I know Samsung is the only supplier for the iPhone X (not sure if that was confirmed), but looking at all these display models, it makes you wonder if another supplier is behind the green/yellow tinted phones, because they aren't even remotely close to the ones with the slight pink edge hue. Even the color shifting is different from what seems like two different batches (with variations in both batches)
If Samsung is indeed the only supplier, then they have some major quality control issues as these inconsistencies are ridiculous. Unless Apple is using an anti-reflective coating (or some other overlay) from two different suppliers which is changing the panel's overall color-tone and tint (and color shifting) on the phones.