Changes to Builder JS libraries are not always immediately applied (particularly a problem for VSCode extension)

There is a related issue #98 (fixed in #105).
But even after the fix, this works not always perfectly.
If I make a change (using VSCode) to a JS library (used by Builder) and re-deploy the code, I see that sometimes the changes to the JS library are not applied immediately.
The workaround is simple: just do several tries and the changes will be applied.