You would have to ask the market why it didn't push it back up, there could be lots of reasons.
Maybe because revenue was flat and that doesn't excite the market, they love chasing growth and buying companies that aren't profitable, but are growing.
Maybe because the results focused on the full year results, which it rightfully had to given it was EOFY, with limited focus on the improved HY profitability.
Maybe the market doesn't quite trust Hills yet and wants to see a continuation of improved profitability before buying demand really kicks in.
I agree with your comment that 17 cents is an important level to hold, but I also see a lot more upside reward from this level than downside risk.
Sometimes if you hold onto the past for too long, you won't see the future right in front of you. I have no history with Hills, so my focus is on the current position of the business and the potential to be delivering $2m+ net profit this half.