Hello,
we have tested Junos 15.1R5.5 on EX2200 and EX3300 again and could narrow down the bug a bit. Authd doesn't work when it recieves an EAPOL Accept for a supplicant. If the switch itself is a supplicant 802.1x it will work with dynamic vlan too.
logs:
"Mar 15 00:10:14.833013 Task receive function invoked
Mar 15 00:10:14.834942 EAPOL packet received on interface ge-0/0/2.0
Mar 15 00:10:14.979179 Creating background job to process EAPOL frame
Mar 15 00:10:14.980764 Entering background job to process received EAPOL frames rx_frame_node_count=1
Mar 15 00:10:14.980974 Invoking state machine for frame received on interface ge-0/0/2
Mar 15 00:10:14.981107 Received an EAPOL Frame...
Mar 15 00:10:14.981304 Frame is targetted to this machine...
Mar 15 00:10:14.998035 EAPOL Frame Received on Port: 73 !!!
Mar 15 00:10:14.998251 pnac_ng_is_native_ifbd_marked_for_deletion:202 native vlan of port 73 NOT-MARKED for deletion
Mar 15 00:10:14.998489 AuthHandleInEapFrame: Received Port based Eap Frame
Mar 15 00:10:14.998761 Port is Authorized, ignore EAPOL-START from another client
Mar 15 00:10:14.998980 Processing complete for frame received on interface ge-0/0/2
Mar 15 00:10:14.999131 Deleted background job to process received EAPOL frames
Mar 15 00:10:32.269090 pnac_auth_client_receive: receive job not found - creating now
Mar 15 00:10:32.269752 Received message from authentication client
Mar 15 00:10:32.269899 reply: 32cd20 rply_hdr: 337004 bytes_remnant :0 len:-1 reply_len:4480
Mar 15 00:10:32.270047 Error reading message from socket. errno = 60
Mar 15 00:10:32.270322 pnac_authd_client_cleanup_socket
Mar 15 00:10:32.270452 Creating socket to connect to authentication client
Mar 15 00:10:34.307968 authd connect failed. authd may not be running
Mar 15 00:10:34.308158 Error reconnecting to authd on connection close
Mar 15 00:10:36.297064 authd connect failed. authd may not be running
Mar 15 00:10:36.297254 Error reconnecting to authd on connection close
Mar 15 00:10:38.298536 authd connect failed. authd may not be running
Mar 15 00:10:38.298769 Error reconnecting to authd on connection close
Mar 15 00:10:40.298923 authd connect failed. authd may not be running
Mar 15 00:10:40.299113 Error reconnecting to authd on connection close"