Problem with an undefined file in ext.js (main.js)

I am on a project where there is a stage, dev and localhost. on stage and dev, when the page loads, I get an error enter image description here

it does not break anything, but you need to get rid of it, I changed the bootstrap file, but after the build it resets to its original state, as I understand it, this is a problem with ext.js itself, but what should I do, how to make sure that this error does not happen