If you are having issues with Instagram and hashtags, you are the ones causing the problems, not Instagram. I've been growing 5 Instagram accounts for 3 years, now I'm growing 12. Each posts 4 times a day with 40(edit 30, I always mix up the number) hashtags in the comment section, however initially they were only posting the hashtags in the first caption box. I never ran into any trouble, ever, unless the hashtags were over the limit. If the hashtags were over what they instructed, the comment section started working weird. As long as you follow the rules they put out for you, there should be no problem.