iOS Calendar Dots disappearing

Have iphone 6 plus, iOS 9.1. So...Sometime last spring I noticed when using the iOS calendar, the dots would disappear for holidays and personal events that I entered. I went to an Apple Store and was told to wait for an update. Well, fast forward to today and my dots are still disappearing. How you may ask? This occurs when I view my calendar in single month view, move forward two or more months, and go back to the current month, or month I was originally looking at. The dot(s) are gone. However, if I press on the date, the event(s) and/or holiday is still there. Example: Nov 26 is Thanksgiving. Nov 27, I'm off. Both have dots. If I scroll to January or further, and scroll back to November, the dots for either the Nov 26th or 27th, or both, are gone. However, if I press on the 26 or 27, Thanksgiving and my off day are still listed. I spent about an hour at the Apple Store recently and was told they never saw this before. After several tests, he deleted my calendar and put "test" dates in and it still happened. He said "weird". Was told to go home, backup phone and restore. To make a long story short, ended up doing a restore, factory reset, restored as new, received a new/replacement, and still same issue. I then spent hours on Apple chat and my issue was escalated to an engineer. I am now waiting to hear back. I have read very little of this issue online. I did read that this issue may only affect the "plus" models. So, I went to work and checked with friends. Four of five iPhone 6 plus models did the same thing. However, none of them use the iOS calendar app so they never noticed this before. Yesterday, I went to the Apple Store to test the display models. Before doing so, I showed the rep what was going on with my phone. He said he has never seen this before. We then checked 5 display models and the same thing occurred. He then called over three reps and should them. Same response. Never seen this. When leaving the mall, I checked some AT&T models and only one of three did it. So, has anyone else experienced this? Mine was occurring before iOS 9. Also, it has nothing to do with my Apple ID. Waiting for an update is getting old since I've been waiting since last spring. And when I asked the 4 reps who experienced this if they could report it to someone, they just said, "apple will find out sooner or later".