1. The generated WHERE clause (which Skuid Model Conditions are translated to for Salesforce) may only be 4000 characters in length. 2. The total generated SOQL query may only be 20000 characters in length.
If you are running into this limit, I would strongly consider rethinking your approach to adding dynamic conditions. In particular, consider trying to use the "Result of Subquery" Condition type to limit a Model to records with a related record in another object.