Good day, using movistar.com.pe.ini I realized that when you set the timespan to 4 or more, an error appears, but when you set it to 3 or less there is no problem.
This is the file: https://github.com/SilentButeo2/webgrabplus-siteinipack/tree/master/site...
Usually this error appear when you call up a page and start date is empty, because the page is empty. All i can say set to 4 days (timespan=3) ....you may want to check the site, if has 5 days or more let me know.
it's true, it's like you say, it only has 3 days available,makes sense now
https://www.movistarplay.com.pe/tv-guide/epg