Yes, that's a bug the forum comes with



If you got IE in use, click the desired file. You will get options what to do:
Choose "save as" and type in the name of the file including its format (.xlsx), select the folder where the file should be saved and click ok.
From the folder you can open the file normally.

Some of the sheets I apply this formulas to has more and some has less rows. Can I not just go in the formula and change the range ($d$2:$d$69) just change the 69 to say 300 and the other corresponding parts to expand for more rows in other sheets. I tried that and now the data returns as Zero or extremely off.

As I said - Yes you can, as long additional range is really empty, AVERAGE() ignores these cells. Empty means, that the additional cells may not filled with Zero neither with empty strings (="") as formulas might return.

The formulas used are Array-formulas. They tend to be slow, therefore it's recommended to keep ranges short for performance issues.

If you do any changes remember you will have to quit the changes by pressing Ctrl+Shift+Enter at one time instead of only Enter. With this Excel will then suround the formula by {} to mark the formula as Array-formula. Only that way the formula will return correct results.

Edit:
As to your second question, it's probably the result of above said