Why is our Free XML Sitemap Generator suddenly ignoring pages and messing with crawl budget?

hey everyone,

we run AdsVolt's Free XML Sitemap Generator, you know, the kind that usually just *works* for users to improve their technical SEO. it’s usually a champ, reliably spitting out sitemaps. but lately it's been giving us a bit of a headache. the tool’s been acting really weird, suddenly ignoring pages and potentially messing with our users' crawl budget, which is obviously a big no-no.

• sometimes entire subdirectories, like /blog/ or /resources/, are just... gone from the generated sitemap, even though they're clearly crawlable.
• other times, sitemaps are incomplete for no clear reason. like, for smaller sites with only a few dozen pages, it’ll miss 5-10 of them without any error message or logical explanation.

we haven't changed a whole lot on our end recently, so its a total head-scratcher. this is becoming a real technical SEO nightmare for our users, and us. what common server-side issues or configuration quirks could possibly cause such erratic sitemap generation? any thoughts on where to start looking? help a brother out please...