From my understanding, these error statements are likely caused due to path issues when the cache is not up to date.
You may try the following steps to resolve the issue.
Before modifying the search path, it is important to take a backup of your 'pathdef.m' file, which can be located by using the following command. Ensure that the copy is placed in a folder outside of the MATLAB path.
After taking the backup, please execute the following commands in the MATLAB Command Window to restore the default MATLAB search path and rehash the toolbox cache:
>> rehash toolboxcache
After this step, please use Simulink to see if the issue occurs again. If the issue is resolved, then you may want to save the new MATLAB search path by executing the following command:
NOTE: This will remove any custom paths you may have created.
The following MATLAB Answers post is an additional resource on how to back them up: