What should I do if I see numerous air bubbles on top of Sikaflex Crack Flex Sealant, after hours of dry time?

If the joint is deep or very narrow (past the 1/2” depth limitation), the sealant will travel down pushing the air out. Most bubbles will pop but if they reach the surface when the sealant is "skinning" over, they will not. It is also recommended to keep the nozzle in the sealant while dispensing. You can apply another layer of Sikaflex Crack Flex Sealant on top, to hide the voids. (This information applies to Sikaflex+ Crack Flex Sealant product line).