Mowlana vs. Mowlanal in Part 6 of Du'a

[CyberMomin]

In part 6 of Du'a when we recite the names of the Imams, sometimes we say Mowlana and sometimes we say Mowlanal. Does anyone know why this distinction is made? Is it grammatical? Or is there a deeper significance (e.g. concealment, use of titles, or some combination)?

[Admin]

I think particularly the names [titles] of the Fatimid Imams, they start with al-**

For example al-Mehdi so we will say Mowlana al-Mehdi or it would sound as Mowlanal Mehdi