Regression with afp-showmount on nmap 7.80 #2091

[user@quinn ~]# nmap -d --script=afp-showmount -Pn -p548 -n xx.xx.xx.xx
Starting Nmap 7.80 ( https://nmap.org ) at 2020-08-01 11:08 CDT
--------------- Timing report ---------------
  hostgroups: min 1, max 100000
  rtt-timeouts: init 1000, min 100, max 10000
  max-scan-delay: TCP 1000, UDP 1000, SCTP 1000
  parallelism: min 0, max 0
  max-retries: 10, host-timeout: 0
  min-rate: 0, max-rate: 0
---------------------------------------------
NSE: Using Lua 5.3.
NSE: Arguments from CLI: 
NSE: Loaded 1 scripts for scanning.
NSE: Script Pre-scanning.
NSE: Starting runlevel 1 (of 1) scan.
Initiating NSE at 11:08
Completed NSE at 11:08, 0.00s elapsed
Initiating SYN Stealth Scan at 11:08
Scanning xx.xx.xx.xx [1 port]
Packet capture filter (device enp0s25): dst host yy.yy.yy.yy and (icmp or icmp6 or ((tcp or udp or sctp) and (src host xx.xx.xx.xx)))
Discovered open port 548/tcp on xx.xx.xx.xx
Completed SYN Stealth Scan at 11:08, 0.09s elapsed (1 total ports)
Overall sending rates: 11.00 packets / s, 484.06 bytes / s.
NSE: Script scanning xx.xx.xx.xx.
NSE: Starting runlevel 1 (of 1) scan.
Initiating NSE at 11:08
NSE: Starting afp-showmount against xx.xx.xx.xx:548.
NSE: afp-showmount against xx.xx.xx.xx:548 threw an error!
/usr/bin/../share/nmap/nselib/afp.lua:2041: bad argument #3 to 'unpack' (initial position out of string)
stack traceback:
	[C]: in function 'string.unpack'
	/usr/bin/../share/nmap/nselib/afp.lua:2041: in field 'decode_dir_bitmap'
	/usr/bin/../share/nmap/nselib/afp.lua:1010: in method 'fp_get_file_dir_parms'
	/usr/bin/../share/nmap/nselib/afp.lua:1673: in method 'GetSharePermissions'
	/usr/bin/../share/nmap/scripts/afp-showmount.nse:85: in function </usr/bin/../share/nmap/scripts/afp-showmount.nse:46>
	(...tail calls...)

Completed NSE at 11:08, 1.45s elapsed
Nmap scan report for xx.xx.xx.xx
Host is up, received user-set (0.076s latency).
Scanned at 2020-08-01 11:08:39 CDT for 1s

PORT    STATE SERVICE REASON
548/tcp open  afp     syn-ack ttl 51
Final times for host: srtt: 75885 rttvar: 75885  to: 379425

NSE: Script Post-scanning.
NSE: Starting runlevel 1 (of 1) scan.
Initiating NSE at 11:08
Completed NSE at 11:08, 0.00s elapsed
Read from /usr/bin/../share/nmap: nmap-payloads nmap-services.
Nmap done: 1 IP address (1 host up) scanned in 1.94 seconds
           Raw packets sent: 1 (44B) | Rcvd: 1 (44B)