Hi Charles. It could be that due to Mozscape going after a wider diversity of domains, they're not crawling as deeply where your clients have local links. Here's Rand's explanation from the Jan 27 update:
The second is that we crawled a massively more diverse set of root domains than ever before. Whereas our previous index topped out at 192 million root domains, this latest one has 362 million (almost 1.9X as many unique, new domains we haven't crawled before). This means that DA and PA scores may fluctuate more than usual, as link diversity are big parts of those calculations and we've crawled a much larger swath of the deep, dark corners of the web (and non-US/non-.com domains, too). It also means that, for many of the big, more important sites on the web, we are crawling a little less deeply than we have in the past (the index grew by ~31% while the root domains grew by ~88%).
Bolded for my emphasis. If you cross link from your client sites to their local review listings to help / prompt users to fill out reviews you're likely to see more of those pages indexed in OSE. However, they could still be not counted if they're not considered important enough for that domain, i.e. if they're not in the top 1000 Yelp pages on yelp.com (numbers are just for example purposes of the idea... not accurate). Make sense?
Google however still likely knows about the links and is applying the related associations. And feel free to use other tools (GWT, aHrefs, Majestic) when trying to create a complete backlink profile for clients. Cheers!