Dash Background Callbacks: significant pre-callback overhead times

General question:
A deep dive video from Plotly on background callbacks indicated (starting at 11:30) that there is “a little bit of” overhead before and after a background callback, but I’ve noticed a significant overhead for one of my apps that typically has a long app initialization time on load.

In addition, I’ve added “timers” (that print timing of processes throughout the file) in my index.py and app.py files that are loaded upon initialization of the app, and noticed that these timers are being triggered again (sometimes mutliple times) when I trigger the background callback. (NOTE: the page does not actually refresh, but it just seems that the app is reinitializing based on these timer print outs)

Has anyone else seen similar behavior (i.e., “app reload” before start of background callbacks)? (apologies I do not have code to show at this time, but will see if I can prepare a mock set in the future).

NOTE: I also have timers at the start and end of the callback itself, so I know that the total time from when a button is pressed to when I get my result is much longer than what I’m timing within the callback itself.

Thank you!