When using a ssh-exec with yum install a timeout occurs.
It seems that is a problem with the progress bar that won't be displayed during the build but after.
At the end of the build you can see that for each output a line is produced.

(3/5): package-a- (29%) 26% [=== ] 421 kB/s | 20 MB 02:14 ETA
(3/5): package-a- (29%) 26% [=== ] 402 kB/s | 20 MB 02:20 ETA
(3/5): package-a_f- (29%) 26% [=== ] 348 kB/s | 20 MB 02:42 ETA
SSH: Disconnecting configuration [rpm target] ...
ERROR: Exception when publishing, exception message [Exec timed out or was interrupted after 240.653 ms]

It seems that these outputs are not recognized during a build which leads to a timeout.

Possible workaround: Turnup timeout

Caveat: you don't know whenever the build is running or stuck...