Memory leak of gnome shell under ubuntu 18.04 LTS

After some time gnome shell uses 62% of the memory, I also had several times situations where the memory consumption did go to full system memory (16 GB) & swap (also 16GB) usage, meaning the system almost didnt react anymore.

I saw this happening mostly when using the Unity3d editor and importing many assets into my project. - in my example it was about 10 assets using around 30 GB diskspace after import. (without unity import compression) - hint: unity3d editor memory usage was between 2-3 GB while processing asset import.

When I enable the Unity3d import compression option, most times my gnome shell goes out of memory. Interstingly the jumps in memory consumption often happens abrupt and intensive increase in memory consumption of gnome shell happens.

output of top command looks like this:

Tasks: 370 total,   2 running, 276 sleeping,   0 stopped,   0 zombie

%Cpu(s):  0.7 us,  0.7 sy,  0.0 ni, 98.6 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st

KiB Mem : 16433216 total,  2408424 free, 12670052 used,  1354740 buff/cache

KiB Swap: 16777212 total, 13281532 free,  3495680 used.  3854292 avail Mem

  PID USER      PR  NI    VIRT    RES    SHR S  %CPU %MEM     TIME+ COMMAND

 2205 root      20   0  631764  93784  83004 S   5.9  0.6  11:30.75 Xorg

 2759 don       20   0  797824  18500  11940 R   5.3  0.1   0:26.45 gnome-term+

 2319 don       20   0 16.578g 9.772g  55892 S   4.6 62.4  14:16.38 gnome-shell