voiceover's focus shifts to the text label but does not get read

Question

While trying to create pdf forms from third party service (formio) accessible, I ran into this weird issue, where when a user steps into the iframe labelled as "iframe 2" the voiceover's focus shifts to the text label "BIO Data" but it does not get read by the voiceover.
The iframe has been added using inline iframe, I have also attached a codepenio demo :

<iframe class="interactive is-tabbed-standard-height" width="900" height="500" src="https://pro.formview.io/#/eaalrbwfwiweuge/dummyform?header=1&reset=1" title="some pdf form created using formio " allow="clipboard-write" loading="lazy"></iframe>

As a consequence, user has to again press ctrl + option + right arrow in order to make voiceover read the text label. Can anybody please help why isn't voiceover automatically reading out the text label when it gets focused.

Note : This does not occur while using NVDA on windows.

Attachments :
[1] video demo link : https://streamable.com/m40v9f?src=player-page-share
[2] codepenio link : https://codepen.io/anyonesomewhere/pen/jORdPyj