Toddler diaper rash

My 18 month old has never had an issue with diapers. We’ve used Pampers, Luvs, Huggies, Dollar General brand, cloth diapers, but we started using Hello Bello here recently, have been for probably 3 months. After that, my mother in law bought us Sam’s Club diapers, and ever since then he’s seemed to have a diaper rash. We stopped using them after a few days, and it did go away for probably a week. Now, it seems like all diapers are giving him a rash, not on his anus, but his butt cheeks and legs where the diaper rubs. We have never had this issue. We have been using Luvs due to financial difficulties, but I plan on trying Hello Bello back out since we had no issues with them, it’s just weird that this started happening after we started using those.

Also, his diaper is not too small, the tabs still go pretty close together. It’s freezing where we live, so I also don’t think it could be heat rash.

Any ideas??