I think this is just a delay. It can take up to a few minutes for Google to notify Glide that a change has been made within the sheet. Are you using 1 or 2 apps pointing to the same sheet? If you are using 1 app, then I think using the new If-Then-Else column would give you a quicker response time. If you are using to apps, then the formula in the sheet would probably be the best option, but you just have to wait.
You can also use our new If Then Else column to make switching faster, but this is likely a delay in coordination between two apps. We have plans to speed this up when using multiple apps with the same sheet.
Ultimately it does update after 2 or 3 minutes so it’s manageable just switch it 5 mins before open and 5 mins before closed till its available for real time update