There was high humidity when stain was put on. Some areas are dry other areas look shiny and are tacky. Can I take turpentine on a rag and wipe over shiny areas to absorb the excess stain that is tacky to speed up drying?
Much to your Chagrin, the stain was probably applied a little thick where it will not dry thoroughly. Mineral spirits will wipe away some of the excess, but this will also wipe away some of the color.
On the other hand, if you do not remove some of the excess, these spots will eventually peel as it will become somewhat of a varnish.
I would recommend a pressure washing and re-stain.
To pressure wash, do not spot wash. Use the wand and follow each board individually from one end of the deck to the other. Try to not dig holes with the pressure but allow the width of the spray to cover the width of the board.