Different behaviour for pg_ctl --wait between pg9.5 and pg10

I have a script where after a point-in-time recovery I run 

"pg_ctl start -D /data -w -t 86400" 

and then try to connect as soon as pg_ctl finishes. With Postgres 9.5.9 (on Centos 7.4) I can connect at the end. But with Postgres 10.3 I get a connection error 

psql: FATAL:  the database system is starting up 

It seems with Postgres 10.3 the postmaster.pid file state goes from 'starting' to 'standby' to 'ready' but pg_ctl is saying the server is ready to accept connections even though the postmaster.pid file says 'standby'. 

Thanks,

Greg