I've seen posts about a similar problem of laquered 7.62x51 cases, these were a particular Germanicon lot headstamped MEN or something like that.
The people discussing these seemed to conclude that the cartridges were intended for the roller locked rifles with the chambers fluted to provide a gas cushion to prevent the case from grabbibg the chamber wall. The heat of discharge softened the laquer, but in the auto rifle it had no deletrious effect. The seconds in sat in a bolt action chamber on the otherhand would let the laquer grip the chamber.

Perhaps some 7.62x54r ammo intended for MGs or the Dragonov had a similar coating.

As for oiled cartridges testing recounted in Reynolds Lee Enfield book suggests that oil caused very little problem unless a large glop of it was between bullet and chamber neck, but water on the cases could cause a greater increase in pressures since water is incompressable. If the case neck can't expand to release the bullet chamber pressures go up. Bullet upset begins before the bullet leaves the case.

BTW
Colonel Jim Crossman, noted authority on international competition and son of Captain E C crossman, was one of the expert witnesses involved in determining the cause of the Enfield breech blow out that killed a hunter in the US in the 1960's.
I haven't found my original source yet but did find and article written by Crossman in which he mentions the case.
The ammunition was manufactured by Federal, it was a common closed base hunting bullet not the open base tublar jacket bullet or Dum Dum.
The base of the recovered jacket was blown inwards, the core blown out.

Similar core blowouts or blow throughs were common with the 1903 loading of the US .30 loaded with hot burning double base powders. Erosion was determined to be the cause.
Record found here.
Full text of "Annual reports ..."