I do wonder if some of those organic solvents you used to clean the chain leave a residue that affects the wax. Honestly I ride my squirted cross bike through wet and mud all the time, and it doesn’t get tacky. I’d wash that chain in hot water (with soap), and see if it gets clean. Then just let it dry a bit and apply squirt afterwards. Leave all the mineral spirits etc off. (If hot water doesn’t work to clean it, you know you got something other than wax in there for sure. But I’d think its dissolved in the wax now and will come off with it.)