Did you ever find a solution to this? We had a fresh install of SharePoint 2013 and deploying InfoPath 2013 forms through Central Admin automatically deploys to 14 hive instead of 15.
I have tried SharePoint Management Shell command
Install-SPSolution 4f426b58-6f42-af62-2678-8b3c33bb722c.wsp -CompatibilityLevel 15 -force
This works however, it adds an extra step. And when you update your form & republish, it goes straight back to the 14 hive.
I have an error for every InfoPath Form:
File
[Features\FT-01-0522a05g-e22-f459-0205-c3fb78046d3a\solution.xsn is referenced
[1] times in the database [WSS_Content], but exists only under Microsoft
SharePoint Foundation 2010 setup folder.
Consider upgrading the feature/solution which contains this file to the
latest version.