Solution operation fails to update

Please follow the forum guidelines and add a minimal working code example that reproduces your issue, Read before posting: How do I get my question answered?
Especially notice:


A MWE is the simplest piece of code that reproduces or explains the problem you have.

It must be possible to take the MWE, paste it into a file and run it, without any extra modifications. Good MWEs can be as little as 10 lines of code. 
If you can remove a line of code from your MWE and still show your problem, then you don’t have an MWE!