Unable to open grib files with irregularly spaced grids?

I want to access data in grib files using readgeoraster. The function can indeed open grib files with data on a regular grid (in my case an ERA5-reanalysis variable at 0.1 degr x 0.1 degr spacings, from the CDS), but it appears to fail when trying to open a grib file with data on an irregular grid (in my case an ERA5 reanalysis variable distributed over a sparse Gaussian grid, N320, also from the CDS).

The error message I get is:

Error using georasterinfo (line 45); Unable to read 'download.grib'. Format might not be supported, file might be corrupt, or a supporting file might have been specified.

Is this a known problem?

What to do about it? Should I file a bug report?

[Torsten]

Before reporting a bug, you should first contact support with your .grib-file enclosed.

[Andreas Baas]

yes good point, I have done so now