Night mode won't stay on

[Android Central Question]

My S9+ finally got the Pie update on AT&T. Night Mode will not stay turned on. If I turn it on, hit the back button and immediately go back to Display settings, it is turned off. Is this setting incompatible with some other setting? Any suggestions?

 

[krisqz]

Are you using any theme? Maybe it's not compatible.

 

[Richard Bell1]

I solved this issue. I enable Developer mode on the device and Night Mode was turned on in Developer settings. I had not enable Developer Mode prior to the Pie update. I turned off Night Mode in Developer settings and the Night Mode settings now work as expected.

 

[DARK Vader777]

Theme interfering with day/night mode.
I had to revert back to the original theme for my daughter's S9+ and then day night modes finally worked again. She has the theme she wanted now but unusual battery drain. I wiped cache partition and put to sleep apps she really weren't using.

So far so good.
This update though, it isn't stable enough for Sprint.
jmo
Will not install on my note 9 yet!