This form indicates that an action had been completed by the time another action occurred, and the narrator did not witness it. It expresses the result of an action or the fact that it took place. It could be termed as the "unwitnessed past perfect" when compared to the past perfect in -ğan ide.
İşetüwemə qarağanda, qayçandır Dəwləkənnən Stərletamaqqa yul salırğa uylağannar həm bu dambanı şunıñ öçen kütərgən bulğannar. (Əmirxan Yeniki, “Soñğı kitap”)
According to what I heard, they once had decided to build a road from Dawlakan to Sterlitamak and, therefore, had raised this dam.
This form indicates either a future action resulting from specific conditions or a habitual action with a present result. In the latter case, it's synonymous with -ğan bula.
Irtəgə kiçkə klub bötene belən bezneñ tuy öçen xəzerləngən bulır. (Fətxi Burnaş, “Kamali qart”.)
By tomorrow night the whole club will have been prepared for the wedding.
This form indicates that the action expressed by the basic verb will definitely have taken place as the result of conditions mentioned in a given context. It is synonymous with that in -ğan bulır, except that it is explicitly categorical.
Xəzer bez ezlərenə töştek. Berniçə səğəttən alar qamalğan bulaçaq. (Fətxi Burnaş, “Xösəyen mirza”)
We have come upon their track. In a couple of hours, they will have been surrounded.
This form is used in narratives to emphasize that an action has been completed and has produced a result before the time of speaking. It's often used alongside present tense verbs for vivid storytelling.
Almış xan Bolğar ilendə islam dine taratu həm məçet saldıru öçen belgeç sorıy… Bolğar xanınıñ İslam dine qabul itüwe xaqında işetkən bulalar. (Rawil Fəxretdinov, “Bolğar tarixına yaña istəleklər”)
Almış khan asked for a specialist to spread Islam and to get a mosque built in Bolghar… They had heard about the Bolghar khan’s acceptance of the Islamic religion.
💡 It can denote actions that will have definitely taken place at a certain point in the future time.
Ul anı inde sin qaytışqa onıtqan bula.
He will already have forgotten about it when you return.