A product feature that requires the full cycle of planning, designing, test planning, test execution, packaging, documentation, etc. should be put into the main releases.
A patch or a patchset that are release vehicles for delivering the fixes to the products and we should avoid to put product features into it. It will makes the cycle of of delivering patches becomes longer and will actually introduce uncertainties to the patch.
A developer who want to put the features into a patch typically does not mean to create any harms. They have eagers to contribute to the product and should not be discouraged.
We just need to help people to get familiar with the development methodologies.
That is why the in-job training is important for the quality of the products.