Hugo suddenly eats up all memory (10 GB available) for "hugo server"

The installed hugo version (0.54.1) has run perfectly on debian buster but since today it is eating up tremendously quick memory without an end.
The hugo site is pretty small with about some simple sites
My memory installed is 6 GB + 4 GB Swap.
I need to cancel the action before the OS freezes.

I have tried another site which runs without any noticeable memory usage.
When I ran hugo server the last time at this page I didn’t notice any noticeable memory usage.
But today it is screwed up somehow and I have no idea how to fix it :frowning:

Could it be a syntax error?
I haven’t changed any layout files since that time

This is the last entry on hugo server -v:
INFO 2019/04/24 20:57:31 Alias “/tags/page/1/index.html” translated to “tags/page/1/index.html”

meanwhile I’ve installed the sid version 0.55.1-1 but the result is still the same

I found the problem.
I had some larger video clips inside of the static folder.
Without these files hugo runs again