Centos 7 64 bit; CB EE 7.0.0-5247
A simple way perhaps to verify this:
1. Create a 2 node cluster - .215(kv) and .217(index)
2. Create a bucket 'testBucket'
3. Create a collection 'pre-qf'
4. Check the manifest
5. Stop server on .217 and fail it over unsafely
6. On resulting .215 node create a collection 'post-qf'
7. check the manifest
So UID got only monotonically increased.
If you were to repeat the same with KV service on .217, then step 7 would yeild
here the UID got bumped by 0x1000 as expected.