While the influx of programmatic has made ad bidding more streamlined, a new study finds that a significant number of programmed ads have quality issues that breach the International Advertising Bureau’s (IAB) guidelines.

On Wednesday, data analytics company Ad Lightning released “The Ad Quality Report for Publishers,” a report that delved into the quality issues behind live programmatic ads on publisher sites. Looking at millions of live programmatic ads across 50 popular publisher sites, Ad Lightning found that 28% of them infringed on industry standards during the fourth quarter of 2016 and into January 2017.

“Despite the overwhelming success of the $22 billion programmatic ad market, it has created some unintended results and major downsides for publishers and users,” said Scott Moore, CEO of Ad Lightning in an email. “Consumers have become increasingly frustrated with sites that slow to a crawl and jump around as ads load and disrupt the experience.”

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The report identifies four major issues of the 28% that were found to abuse IAB’s standards: they are oversized, over-requested, processor-intensive, and are not SSL encrypted.

Of these issues, the report found that oversized ads were the most frequent. In fact, 41% of tracked ads surpassed the IAB’s approved maximum, which is 200 KB or less for banner ads and 300 KB or less for display ads. And not only did they surpass this limit, but on average, the ads that were studied were nearly four times larger than IAB’s standard, with almost 10% being larger than 5 MB and some as large as 30 MB.

With programmatic advertising, the higher the number of bidders, the longer it takes for an ad and the surrounding content to load. Therefore, the IAB suggests that a single ad shouldn’t receive more than 15 bids. In reality, that number is much higher. The study found that the average number of bid requests per ad is 56, nearly 4% higher than the standard.

Processor-intensive ads, often video ads, can also cause page delays. The study found that about 32%, or one third of ads studied, were processor-intensive, exceeding IAB’s limit of 300 milliseconds to render. Indeed, 12% of ads took more than 500 milliseconds.

Furthermore, the IAB has suggested the digital ad industry to adopt SSL encryption, a link that protects the data that passes through web servers and browsers. The study found that 51% of bids were not SSL encrypted.

See also: How pharma can stay compliant when using programmatic

These issues are making programmatic a double-edged sword. Websites that demonstrate slower page loads and more disruptions scare visitors away, consequently hurting publishers’ ROI, said Moore. He points to a study from The Aberdeen Group which found that a one second delay on a webpage reduced the number of page views it received by 11% and customer satisfaction by 17% and a recent Google study that found that mobile sites that load in five seconds see up to twice as much ad revenue as those that load at the industry standard of 19 seconds.

Moore said it’s the cumulative impact of a lot of brands, agencies, networks and other ad platforms that are ignoring the guidelines. “We don’t think it’s done with malice intended,” said Moore. “However, awareness of how this is adding up to be a problem is a big step forward in improving brand sentiment and ROI, consumer experience and improving publishers’ own brands, as well as bottom lines. Bad site experience can tarnish a publisher’s brand and drive consumers away or inspire them to install ad blockers.”

This story first appeared in Campaign.