Pam Peters examines this topic in some detail in ‘The Cambridge Guide to English Usage’. She considers the following two sentences:

These kinds of problem are to be avoided.

These kind of problems are to be avoided.

The first, she writes, ‘entails an abstract / noncountable use of the following noun (“problem”), and helps to synthesize the discussion in argumetative and persuasive writing.’ Of the second, she writes, that it ‘is simply a more relaxed form of the full plural construction, and tends to appear in interactive writing and live speech’. If, then, your example appears, as seems likely, in a formal context, then ‘what kinds of patent’ would probably be the one to go for.

Pam Peters examines this topic in some detail in ‘The Cambridge Guide to English Usage’. She considers the following two sentences:

These kinds of problem are to be avoided.

These kind of problems are to be avoided.

The first, she writes, ‘entails an abstract / noncountable use of the following noun (“problem”), and helps to synthesize the discussion in argumetative and persuasive writing.’ Of the second, she writes, that it ‘is simply a more relaxed form of the full plural construction, and tends to appear in interactive writing and live speech’. If, then, your example appears, as seems likely, in a formal context, then ‘what kinds of patent are being issued’ would probably be the one to go for.