Deck Stain and Sealant Problem

Located in Canada. Deck is in Full Sun. Pressure treated wood, 4 years old, unstained previously. Power washed, sanded pre stain/sealant application by a company. I had professional application of a combined water based stain/sealant 2 days ago. Please see photos. The dark areas were applied first, then the staff took a lunch break and applied more using a new pail of product to the remaining sections. The company has offered to come and reapply to light areas, stating that the product was not well mixed. I am very concerned about blending the stain and adherence to the sealed wood. Please see photo #3 with water pooling after a rainstorm today. Please advise on how to proceed. Sadly, I have paid in full.