This might be unrelated to your original question, but the paths you show seem a little strange. You show a Polyspace path but you are using the Symbolic Math Toolbox which is unrelated to Polyspace.
Did you by any chance do an addpath(genpath('C:\Program Files\Polyspace')) to your MATLAB installation to integrate Polyspace and MATLAB? If so, please use restoredefaultpath to restore the default MATLAB path (or at least use rmpath to remove paths starting with C:\Program Files\Polyspace) and then use the official instructions to integrate Polyspace and MATLAB.
I have no idea what the problem could be with R2018a.
Be certain you have downloaded and installed all the Updates. (I believe in R2018a use Add-Ons —> Check for Updates, however if that does not work, try Help —> Check for Updates. That changed, however I do not remember in what version.)