Grok does cite that claim as being from https://countrystudies.us/spain/30.htm a page in Eric Solsten and Sandra W. Meditz, editors. Spain: A Country Study. Washington: GPO for the Library of Congress, 1988.
The nice thing about grokipedia is that if you have counter examples like that you can provide it as evidence to change it and it will rewrite the article to be more clear.
You know what other site you can provide evidence to and change to be more correct?
Not Wikipedia as Wikipedia doesn't care about evidence. Those people care about reputable secondary sources and will ignore you when point out evidence that contradicts such sources.
I don't ever edit English wikipedia because my English is not nearly up to the standard, and suggestions for improvement (worthwhile IMO) are usually ignored. Grok at least won't ignore you. (I tend to post suggestions to unpopular pages with sparse edit history, which is probably the reason for them going unnoticed.)
I use to frequent irc channels and forums where no such thing as an old question existed. Someone asked an interesting question on irc and days or weeks later a response would happen. On forums the response could be more than a year "delayed". Gradually things shifted to newer new new news that couldn't possibly be new enough. Then debates happen where people sometimes link to the vastly superior olds. Wikipedia finally caught up and questions are no longer ignored. In stead they are archived long before an ignored status could be earned.