Ads button missing

For several days now the ad button on dimension jars has been replaced by pay-with-gems button. It's not that I've used up my ads for the day because I only use ads on dimension jars. Plus I still get the ad available symbol when the dimension jar is sitting in my camp. By all accounts I have ads available and I should be able to use them (I generally use them for multiplying breeding crystals), but the button has been covered up or something by the gem button. Any ideas?