This is "normal", you have to be a bit patient with the HR tile. It might have to do with some background loading of data of sorts. You will notice the same one level further, i.e. when you are in the HR tile and want to see the HR profile for a particular day, initially it does not want to open. It may take some time until the data is loaded, and then suddenly it works.
There are similar effects in other tiles. For example, on your Steps tile you may see that it says (f.e.) 5,000 steps, but when you click on the tile and see the overview of steps per day, that last day is hanging behind and it takes a little while to update.
Once you got the hang of all those little things it goes by itself and you don't really notice too much.
