What were you expecting to happen?
Not to get watch triggered on the files I ignored (I ignored "!other_project/node_modules/**/*" and I get triggered on "other_project/node_modules/.bin/uuid").

What actually happened?
Watch is getting triggered on change in "other_project/node_modules/.bin/uuid".

Please post a sample of your gulpfile (preferably reduced to just the bit that's not working)
There is whole repro here. Clone it, do npm install and node test.js.

What version of gulp are you using?
4.0.2

What versions of npm and node are you using?
npm 6.4.1
node 8.15.1
os is ubuntu 18.04.3 LTS