It's actually 4 installations out of 248 they complained about so far - the other 3 were apparently added very recently for the lawsuit only and apparently never told Tesla about them prior July 31.
Also, to quote Tesla's position:
"Of those, 244 systems are offline not because they are inoperable or unsafe, but because Walmart unfairly seeks to exploit claims it asserted - concerning just four other systems - as a pretext for refusing to comply with Walmart's contractual obligations and for demanding concessions from Tesla on all 248 systems. For over a year now, Tesla has made extensive efforts to accommodate Walmart's inconsistent and shifting positions, repeated delays, and unreasonable demands, all at significant cost to Tesla. My client continues to prefer a business solution to this dispute, but Walmart's conduct has put the parties on a collision course for litigation."
I believe it's pretty clear that Walmart
wanted this lawsuit and there's little Tesla could have done to prevent it being filed. People here theorized that a motivation might have been an effort to discredit rooftop solar, which is competing with the Waltons' utility solar interests.