I am in need of some understanding regarding the Shield ability. I am pretty clear on the fact that when you use someone's ability to add Shield to a Unit, it will get removed at your next refresh stage. Does this same precedure apply when the Shield bonus is added to the Unit from an enhancement and then get removed during the Refresh stage. Is it a one time event? or is it permanent, or does it get reapplied. I have been playing it as it is a perminent, but I want to be sure.

Shields are not permanent. They either get used or they get removed during your Refresh phase.

if you mean the shielding keyword, that has the ability to give out a shield when the unit joins a fight, such as granted by aft armour plating
then the unit has the keyword while it has the enhancement

Alright so that is how Soresu Training works, that makes more sense now. Thank you.