TLS server cerificates imported from TinyCA all show validation error X509_V_ERR_EMPTY_SUBJECT_ALT_NAME, but SAN isn't empty

[nupulu]

I have imported all PEM certs for my local root CA and the depending server CA into XCA (PEM certs and keys), and then imported the PEM certs and keys for my servers into XCA. The root CA and server CA certs validate fine. For the server PEM certs XCA shows a validation error of X509_V_ERR_EMPTY_SUBJECT_ALT_NAME. The weird thing is that the X509v3 Subject Alternative Name extension exists for all of them and is NOT empty.

Why would this validation error be shown?

How can I avoid his?