Random pausing due to 6.28.0 - [Firebase/Performance][I-PRF200006] Trace name _st_UIViewController started, not stopped

I am experiencing a significant pause in transitioning on IOS
with the log showing
6.28.0 - [Firebase/Performance][I-PRF200006] Trace name _st_UIViewController started, not stopped
when the ap behaves properly this does not appear.
I have deuced its some form of crash/garbage collection

The app uses the luxand facial rec plugin, which throws up a framed background captures the image and returns it to the typescript as recognised or not.

the code then displays the home.html page which runs through some angular and displays a section with a list to select from. this list as a result of the above can take 20 seconds to be displayed. when the error doesnt appear its instant as expected.

Can anyone suggest places to look to resolve this ?
(or worst case how to turn off firebase crashlytics)