3. the signature I get: IFkS40AxIuRGDN/vnjwavfV6R00h3MKArtDB7tpBbnqIMc6WSGIQm/wm4lN7JVbY6jbeMf27x8VOqI6azgwz2Q==
your signature length is
invalid, it should have been 65 bytes but what you posted here is only 64 bytes which means it is missing 1 byte.
this should not have happened, i can't see any bugs that could lead to this either. are you sure that you have not modified the signature yourself?