Monsters do not spawn in in the river biome

im sure you guys have had some complaints about this one but mobs aren't spawning in a river biome. I've built a mob farm over my house in the mangrove swamp and mobs aren't spawning in it. I think it also has to do with the river since there are so many water features in the mangrove. I just hope this is a quick fix for you guys which I'm upset I can't use my mob farm and iron farm as they are both affected by this bug. i know you guys have a lot on your plate so take your time but hopefully I see this bug fix in one of the next few updates!