grammar - Giving an example of a "problem" where the example is plural

I've got this sentence here:

The most recent problem I can think of is personal knowledge management systems.

That seems grammatically incorrect because of the mismatch between the singular problem and the plural systems, but I can't just change it to

The most recent problem I can think of are personal knowledge management systems.

or

The most recent problems I can think of are personal knowledge management systems.

The only one that seems correct is

The most recent problem I can think of is the problem of personal knowledge management systems.

I think this equates the singular problem to the also singular problem of personal knowledge management systems. But it's extremely awkward. Any suggestions on how to handle situations similar to this?