KNOWN_BUGS: "FTPS needs session reuse"

Closes #4654

docs/KNOWN_BUGS

@@ -78,6 +78,7 @@ problems may have been fixed or changed somewhat since this was written!
  7.7 FTP and empty path parts in the URL
  7.8 Premature transfer end but healthy control channel
  7.9 Passive transfer tries only one IP address
+ 7.10 FTPS needs session reuse
 
  8. TELNET
  8.1 TELNET and time limitations don't work
@@ -588,6 +589,14 @@ problems may have been fixed or changed somewhat since this was written!
 
  See https://github.com/curl/curl/issues/1508
 
+7.10 FTPS needs session reuse
+
+ When the control connection is reused for a subsequent transfer, some FTPS
+ servers complain about "missing session reuse" for the data channel for the
+ second transfer.
+
+ https://github.com/curl/curl/issues/4654
+
 8. TELNET
 
 8.1 TELNET and time limitations don't work