ESA form please help!

My husband was on Incapacity benefit from 2004 until we think 2014 when it changed to Contribution based ESA. He has a PHI, which is not ESA deductible, so gets ESA because his employment contract was never terminated and tax and NI is paid on the money received. I work over 30 hours a week and we have savings over £16,000. A form has arrived for my husband today ESA3(IBR) 06/18 saying "we need to look at your claim again to check you're getting the right amount of money". It goes onto say in a box on the first page "Don't complete this form if during the whole time between (date given in 2014)
You have a partner and they're working for 24 hours or more a week
You have savings over £16,000:or
You have a partner who has savings over £16,000
We don't understand, is a working partner a barrier to contribution based ESA? Why are savings relevant when the form says on the very next page "Your savings will not affect your contribution based ESA"?
Please help me to make sense of this, I am worried sick it's all going to unravel.

Thank you very much for your reply. We've now received a review form ESA50 when my husband was only assessed 2 years ago and has had an irreversible brain injury, for which they've had neurological evidence stating this multiple times. I am so frustrated that the system is so bad, it's like they never read what they get, or if they do actually digest it. I appreciate this forum, the help and the site. I am alone with all of this at times and life is already tough. This is and has been a lifeline for me. Thank you again

Thank you for your response, it helps me to know it's not just him. It feels so personal, so ludicrous too. Under the old system there was a letter saying he'd never have to go through an assessment again as he was so bad! Deep breath