This positioning discrepancy can occur when a widget’s text does not include specified line spacing. Axure RP widgets do not include specified line spacing by default. However, browsers can use a different default line spacing than what appears in Axure RP 8, and this can cause icons and text to appear misaligned when the page is previewed. To ensure that the text is rendered similarly to the Axure RP project in a browser, you can set up specified line spacing values for your text using the Style section of the Properties pane.
This should help the text appear as consistently as possible across different browsers and allow the icons to appear more correctly aligned when the page is previewed.
I hope this helps!