Hi The site was created in SPPB3 and has been upgraded all the way throught to SPPB version 5.3.1 The Native Shotcode has been working I am aware that Since SPPB5 That it has never displayed in preview mode but does in the live site. This is the first version i have noticed it not working.
I use a lot of Regular labs Snippits on this site they are in Raw, and text addons and in some of the titles the work perfectly and are continuing to do so in this version 5.3.1 they have the same issue that they don't display in preview mode but do display in the live site
The link below is one of 70 pages using both Regular labs Snippits and native shortcodes As mentioned these do not work in preview mode but do in the published site. I use them mainly for the contact details of the agents which are replicated all over the site this means its simple to keep the agents details uptodate only having the one instance to update.