The Saudis are fed up with OPEC members not meeting output goals, according to a Bloomberg report. The Saudi Energy Minister reportedly told Al Arabiya also seeking more transparency from Russia.
Those comments might be seen as a warning that if quotas and pledges aren't met, they will flood the market; or at least they won't continue with 1 mbpd cuts beyond July.
From where I stand, compliance hasn't been a big issue but there may be games played with exports and production below the surface.
I find it strange these stories of a rift are delivered month after month (usually in the WSJ) and they continue to work together.