@Jan, yes I agree the root cause is the CSI Driver doesn't respect the fsType, every fsType will be propagate to pv info even using a invaild value like "aaaa", and the fix should be reject such provisioning.
On the other hand, EFS actually don't support the XFS or EXT3/4, so FSType: "" also stands for the same meaning here? Is it possible to disable it to avoid the confusing?

I think that FSType: "" is OK to show that it's not known / default. For block volume based volumes it's useful to show if it's ext4 or XFS (if Kubernetes knows it), because it may behave differently, but for EFS there is no such choice, it's always NFS.

Verified. 
Status: PASS

Release Version: 4.10.0-0.nightly-2022-01-27-221656
EFS Version: 4.10.0-202201261535

Tests:
1) With fstype: efs: pod running fine. 
rohitpatil@ropatil-mac dynamicprovi_done % oc describe pv pvc-952c5342-13e1-48e8-9fa2-6c58c1c8993c -n testefs
Source:
    Type:              CSI (a Container Storage Interface (CSI) volume source)
    Driver:            efs.csi.aws.com
    FSType:            efs
    VolumeHandle:      fs-041b39066187fbf36::fsap-0011da27dc6d91cc9


2) With nonfstype parameter: pod running fine.
rohitpatil@ropatil-mac dynamicprovi_done % oc describe pv  pvc-873afa64-066d-4e9f-8df0-08b1320d1a07 -n testefs
Source:
    Type:              CSI (a Container Storage Interface (CSI) volume source)
    Driver:            efs.csi.aws.com
    FSType:            
    VolumeHandle:      fs-041b39066187fbf36::fsap-05699bded0750b1cc


3) With any other fstypes parameter: pod/pvc will be in pending state with error message:
rohitpatil@ropatil-mac dynamicprovi_done % oc describe pvc efs-claim -n testefs
Events:
  Type     Reason                Age               From                                                                 Message
  ----     ------                ----              ----                                                                 -------
  Normal   Provisioning          3s (x6 over 34s)  efs.csi.aws.com_ip-10-0-79-158_6489a227-f449-47b5-9b31-1e8f0ab81f92  External provisioner is provisioning volume for claim "testefs/efs-claim"
  Warning  ProvisioningFailed    3s (x6 over 34s)  efs.csi.aws.com_ip-10-0-79-158_6489a227-f449-47b5-9b31-1e8f0ab81f92  failed to provision volume with StorageClass "efs-sc": rpc error: code = InvalidArgument desc = Volume capabilities not supported: invalid fstype: nfs

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (Moderate: OpenShift Container Platform 4.10.3 security update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHSA-2022:0056