Product and version: FileMaker Pro and Advanced v126.96.36.199
OS and version: Mac OS X 10.10.5 & Windows Server 2008 R2
Hardware: 2010 iMac, 2013 15" MacBook Pro & VMWare Server
Following the 188.8.131.52 update for FileMaker, the Get(ActivePortalRowNumber) function behaves differently to FileMaker 14 and earlier when running the function on a new record.
To reproduce, enter a value in the blank portal row (to create a new related record). Run the function without leaving this field (i.e. before the new record has actually been created). In FileMaker 14 and earlier, Get(ActivePortalRowNumber) will return the portal row number as expected. In FileMaker 15 following the v184.108.40.206 update, the function returns 0. This is an unexpected change in behaviour which broke one of our scripts.
As a workaround you can move to another field on the portal row before invoking the function, which causes FileMaker to actually create the new record and report the correct portal row number.