Pinholing happens all year round No matter the temperature with higher concentrate thin coat like Johnstons,
When you mix with a paddle mixer on a thick concentrate it trains air in and trap’s it
Johnstons takes a litre of water to bring it to the same Viscosity as others on the market allowing the air to rise and disperse,
If you add your water or Excelerator and knock it up the day before give’s time for the air to disappear, won’t happen again