macOS 10.15.5 broke mouse pointer location on vertical display

@rynop2000 - did you hear anything more on this? Still happening for me.

Same problem here, as described above, I had a replacement laptop on 10.15.4 and it worked fine, but I accidentally updated and the issue came back :(

1440p center horizontal no scale, 4k 90 degree left side scale 1440, 4k 270 degree right side 1440 scale, MBP 16

Nothing I can do fix the issue, I have to position my windows to avoid the issue, super annoying!

Ah, having this same issue, its so annoying! Since the last macos update - I've noticed that if i use the 'default' size (everything massive) doesnt happen and also with the tiniest text size, but both of these options are not very good on 4k screen.

I'd like to reiterate here and confirm that i too am experiencing the exact same problem as well.

I have an external 4K ViewSonic VP2780 SERIES, and when set to 90 degrees and scaled in display settings, the problem with the mouse pointer position outlined in this tread persists.

It seems to disappear toward the right edge of the screen and/or clicking in that area does not target the correct position of the mouse. For example, when attempting to click the Search icon in the menu bar, the Siri icon is selected instead.

I've noticed this issue only occurs with HiDPI(scaling) enabled. For example, inside SwitchResX, I can change between the same resolution but HiDPI enabled/disabled. I've noticed it on all supported resolutions for my vertical monitor.

Adding to this thread. I have a newer 16" MBP, running OSX 10.15.7 with an external monitor rotated at 90 degrees.

It definitely a weird UI bug. I've had to retrain myself to offset my clicks when close to the right side of the screen.

There's this invisible vertical stripe about 1.5" off the right of the monitor that runs the full length of the screen. To find it, you have to move the mouse pointer across that area very slowly (either direction works). The speed is key -- too fast, and the pointer skips over. As soon as the mouse pointer encounters the invisible stripe, the pointer suddenly vanishes as if into another dimension(?). You can scroll another approximate 1/2" before the pointer suddenly re-emerges, right about where it vanished. I wonder if this pocket-dimension screen-fold results in a calculation error between where the mouse pointer is positioned on the screen, and where the actual click happens. For my setup, click errors only happen on the right side of the stripe.

My mbp 16` has this problem for a year.

I called to the Apple Service, they could not fix it.

So i waited for a year, but NOTHING HAS CHANGED!

I am using 2 external monitors, one is vertical.

In addition to this, i have another one. If i close macbook and connect to my monitors, the scan rate of my monitor drops to 30hz.

Plz, Apple. Fix these problems. There was no problem on 15` mbp.

I am experiencing this exact same problem with a vertical monitor on macOS and would love an update when it's fixed. My awkward workaround is to just not use the rightmost 15% of my screen.

I noticed a fun thing, If you try to make a screen recording of it happening, it shows the mouse in the "correct" place, i.e. where the clicks happen, but not where its shown to you on the screen.

Try to do what I mention above then tell me the result.

And If anyone else have updated to Big sur please confirm this issue was Fixed or Not.

For me, nothing was changed. Very very disappointed