readwfc - compiler issue

[NFH]

Dear all,

I am using the latest EPW5.1.0 embedded within QE6.4.1 release. After successful self-consistent/non-self-consistent and phonon runs I get constantly the following "infamous" read-in error while running EPW:

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
task # 0
from readwfc : error # 20
error opening wfc file
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

I am aware of some discussion in this forum on this topic, but I can't find a consistent solution to this problem in these threads. There's a hint it might be a compiler issue, so I tried combinations of
-openmpi_1.8.8_intel_studio_2018 or openmpi_4.0.0_intel_studio_2018
-intel_studio_2016.1.056 or intel_studio_2015.0.090 or intel_studio_2018

All of them give rise to the same problem. Same holds for the EPW5.0.0 version.

Is there a final solution to this problem or a statement by one of the developers, wether this problem is entirely compiler related?!

thanks a lot in advance!
Nicki