Steps
1. Have Iron Bars and Glass pane on a flat surface not touching any blocks on the side of it
2. Place a barrier block next to them.
Expected results: In 1.8.9 barrier blocks did not connect to Iron Bars or Glass panes when placed next to each other.
Actual results: In 1.9.2 Iron bars and Glass panes connect to the barrier block when placed next to it. This doesn't happen with any of the fences such and wood or cobble.
Duplicate of MC-94016, if you have not,mplease use the search function in the future to see if your issue has already been reported.