Not (!) operator appears to not work

[jv123]

I have a straightforward section of code that checks to see if an ID of a SharePoint List exists.

!IsEmpty(
LookUp(
Projects,
'ProdjCode' = projNum.Text,
ID
)
),Notify("Proj Number Already Exists"),

Although the ID clearly does not exist because the ProdjCode I am entering (007)  doesn't exist, it still evaluates to "True" and gives me the notification, "Proj Number Already Exists" which is incorrect.

[jv123]

OK looks like switching !isEmpty with !isBlank did the trick. Someone needs to get the world out that !isEmpty is no longer reliable for these kinds of scenarios. Thank you v-liwei-msft. I truly appreciate it.

Microsoft should seriously publish these changes so people don't waste valuable time on trying to figure out what went wrong when you guys change things. It drives people insane and a HUGE turn off for people when trying to choose which platforms to use which is what I am doing now. I have seen several scenarios like the one below that should have worked but now it doesn't work as it seems and apparently I need to use something else (the solution in this post).

https://powerusers.microsoft.com/t5/Building-Power-Apps/Prevent-Duplicate-Records-from-being-submitt...