Why aren't my FB posts showing the correct timestamp (Samsung Tab 4)?

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AC Question

Samsung Tab 4 Timestamp issue

I have the Tab 4, and I find that on various *apps and message boards (such as Facebook) the posts never show the correct time stamp on the day of posting. *It will say "Just Now" all day even if the post was *8 hours ago. *I don't have this issue on my cell which is an S5. *Any insight? *Thanks.