4.5.1 / arrayAppend sometimes does not append value

I do have my own test suite (that includes 69 tests) for application and typical cycle of 1000-cyclic-runs of this suite to evaluate stability. With src-based 4.5.1-2844 (and JavaSDK 2.3.5) i see my tests die sporadically on arrayAppend results check (check is a 10 x sequence of "sync-get-doc / check-content / sleep 1s", so if after 10 seconds there is no needed content, it dies). Check shows, that there is a missing value (always one, but it can be a different value in a different documents within different tests in suite).

More:

• JavaSDK 2.3.5 and src-based build 4.5.1-2844: guaranteed fail on cyclic iteration 0..40
• JavaSDK 2.3.5 and src-based build 4.6.0-3544 there is NO problem for 1000 iterations
• I cannot reproduced this error with simple standalone arrayAppend-test

So, this is more like "please, keep this in mind", then "reproducable bug", because i'm not sure if this problem is gone for 4.6.0 or it just "hides behind some changes" in 4.6.0