memtier crash with assertion failed for time bound heavy datasize tests

[RobotsThink]

While performing benchmarking on time bound scenarios with heavy data sizes in the range of 8MBs or higher and with higher pipelines of >=8, I am noticing assertion failure.

Example command:
./memtier_benchmark -s localhost -p 6379 --test-time 300 -d 8000000 --pipeline=8 --threads=1 -c 20 --key-pattern=S:S --ratio=1:1
Error:
memtier_benchmark: client.cpp:426: void client::handle_event(short int): Assertion `finished() == false' failed.), -nan (avg: 20648.63) msec

This does not happen when time constraint is removed with memtier ( even though I select higher data sizes and pipelines ).
Also visiting the source code reveals, while finishing the tests, its trying to see if the write-buffer has any bytes left and if it is, then this assertion is thrown. Is this an intentional logic to show that benchmarking did not run clean when the time was fixed.

System details:
Intel DL 380 (Ubuntu 16.04 with default kernel)
RAM: 256GB , free ~247GB