[Grammar] Mixed Tenses

[CaseyA]

How can Africa grow more food? | Global development | guardian.co.uk

Unfortunately, that is what has often been lacking in sub-Saharan Africa.

Why are the two verb (phrases) in different tenses when they refer to the same thing? Would the following be more correct?

Unfortunately, that has been what has often been lacking in sub-Saharan Africa.

 

[Rover_KE]

It has been lacking in the past, and is still lacking now.

Rover

 

[emsr2d2]

And it is a fact now that something has been lacking in the past.

 

[Tdol]

How can Africa grow more food? | Global development | guardian.co.uk


Why are the two verb (phrases) in different tenses when they refer to the same thing? Would the following be more correct?

Many would say that they're not in different tenses- to most linguists, they're both present tense, with one in the perfect aspect.