I experienced this during a 3v3 match. I had Macha in a control group with 2 howling banshee, 2 dire avengers, 2 rangers and 1 dark reaper. I had started an engagement by attacking an enemy Soul Shrine. The banshees charged in, and the ranged units began firing/set-up as normal. When the banshees arrived at the Soul Shrine and started attacking, the nearby listening post was in range to fire on them. So I hit the ctrl-group and selected my squad to focus fire on the listening post. I used a right-click to target the listening post, but all my units continued to attack the Soul Shrine. I assumed it was lag or miss click, so I spammed right-click on the listening post and was getting audio confirmation that my units would attack that target but they continued to shoot the Soul Shrine.
At this point I assumed it was a glitch and continued to try different methods. I selected the ctrl-group and used the attack move order and left clicked on the listening post and something strange happened. Some units continued attack the Soul Shrine, some units decided to attack a nearby enemy warrior portal, NONE of my units would attack the listening post. I tried this attack order several times. An enemy force came to engage my units and I again tried to have my Eldar attack them directly but they continued to be "stuck" to the Soul Shrine and Warrior Portal, as if they had been taunted from an ork unit. (I did not see an indicator as such)
At this point I just retreated my units and fought a battle someplace else on the map. For reference this happened on the 3v3 map, on the southern side, the eastern most resource point with 1 req and 1 pow node.