Tikkurila products are made in Finland for a Nordic market, we do not modify them for the UK.
Not a common issue, however one that occasionally crops up.
Tikkurila have three fully water-based options; Helmi, Everal Aqua and Intact.
Pinholes tend to appear when too low a film build is applied to the substrate.
Blistering is quite common and can be caused by a number of factors.
Fully water-based products dry quickly but cure slowly so it is essential that notice is taken of the CURING times for each individual product.