mochajs/mocha

hi all, hope someone met it before
I am observing strange behavior when I am using "grep" function.
mostly the problem is in this method:
var match = self._grep.test(test.fullTitle());
(node_modules\mocha\lib\runner.js )

from time to time also here (where _grep.test is using):
this.grepTotal(this.suite)
from:

Runner.prototype.grep = function(re, invert) {
  debug('grep(): setting to %s', re);
  this._grep = re;
  this._invert = invert;
  this.total = this.grepTotal(this.suite);
  return this;
};

The problem that method var match = self._grep.test(test.fullTitle()); outputs false, while it should be true, but only for some 'it' (tests). My describe has 2 it, one is passed, the other not visible because of condition 'false'
At the same time, this method Runner.prototype.grep is showing 2 'it', but this thing self._grep.test(test.fullTitle()) is validating only one. In some cases both of methods skips some 'it'.
Example:
this one 'it' not visible:
this is some description @testing @testing-smoke Ensure dashFeeSensitivity exist
while next 'it' works:
'this is some description @testing @testing-smoke Ensure dashMaxFloor exist'

bot of them should return 'true'

/@testing |@testing$|@testing-smoke |@testing-smoke$/g.test('this is some description @testing @testing-smoke Ensure dashFeeSensitivity exist')
/@testing |@testing$|@testing-smoke |@testing-smoke$/g.test('this is some description @testing @testing-smoke Ensure dashMaxFloor exist')

Any help is very appreciate !