Chaos Reach can't shoot through a friendly banner shield super. I've encountered this problem running GM nightfalls. Warlock was wearing Geomag Stabilizer and Titan was wearing Ursa Furiosa. I've talked to other people and streamers and we all had the same issue.
Apparently this bug existed before in Destiny but was fixed in Update 2.1.0 on Nov 27, 2018. Right now it seems to have reappeared.