When using this forum on iOS periodically I get a screen refresh (from embedded page data, not a hosted page) which pops up a fake 'open this in App Store' dialog ... pressing anything then tries to send you off elsewhere (hint: hit back in Safari to avoid). You can try and renter the thread and probably won't see the same problem but 'last read' position is lost. Super annoying. Could a mod raise this with the site owners/hosters? Almost certainly a malware laden third party ads server is the cause.