It's not just you. Any trademark expert will tell you that you only have to use the symbol once, in the first or most prominent place where you use the trademark.
Also when you use other companies' trademarks, you should have a notice of who the trademark owner is, which this press release does for Sitara but not for the other trademarks used in the piece.
Search the page for "disclaimer", or just read the whole article - it has a lot of good trademark advice. It also somewhat disagrees with what I said about only using the trademark symbol once - it says to use it the first time and "occasionally thereafter".
So here is an interview with an IP attorney who suggests just using it once:
> A disclaimer is a statement that you include in your application to indicate that you do not claim exclusive rights to an unregistrable portion of your mark. For example, if you sell shirts and your mark includes the generic word "SHIRTS," you could not object to someone else also using the word “SHIRTS” as part of his/her mark. The word is still part of both marks, but no one is claiming exclusive rights in that word, because it is an 'unregistrable' component of an overall mark. (See below for typical examples of unregistrable matter that must be disclaimed.)
> A disclaimer does not physically remove the unregistrable portion from your mark or affect the appearance of your mark or the way you use it. It is merely a statement that the disclaimed words or designs need to be freely available for other businesses to use in marketing comparable goods or services.
