Depends on your definition of the word bottleneck, if you mean "make games that would otherwise run fine with the 1060 unplayable" - then only in rare instances.
If you mean limit the performance of the gtx 1060 in some games when trying to push max fps, then yes it will 100%.
But the key point is it depends on the game, for single/dual threaded games that arent CPU heavy, it wont bottleneck at all, for games that can scale upto 8 threads, it obviously would.
When people say "it won't happen often".. Battlefield 1, CSGO, DOTA 2, Overwatch will all take a performance hit & they are some of the most popular titles out atm.
Google <game name> + techspot CPU Perf & you can cpu benchmarks for most recent titles.