HYPERLINK() function seems to be remembering an earlier URL value??

Hi,

I created a conditional hyperlink to a Sharepoint doc using

Formula:

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URL1 pointed to a pdf stored on a Sharepoint site. That didn't seem to want to connect, so I changed my mind and pointed the URL directly to the WWW source of the doc (URL2):

Formula:

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URL1 is no longer anywhere to be seen in the formula. When I hover over the Hyperlinked cell, the correct URL2 shows in the popup dialogue box, but when I click on it, my browser tries to go to "URL1URL2". The URL window of the browser shows the two URLs concatenated, and of course can't open it because it is invalid.

How is Excel remembering URL1, and why is it prepending it to URL2? (and more importantly, how can I stop it from happening?)

Many thanks.