My dynamic sitemap validation is failing for... reasons?

It sounds like you're battling the infamous "sitemap validation selective blindness," and trust me, you're not cursed; many of us have pulled our hair out over this exact scenario. It's incredibly frustrating when your sitemap.xml looks perfectly pristine on your end, yet validators scream about missing tags or count mismatches. Often, these issues stem from a few common culprits with dynamic sitemaps. First, aggressive server-side caching or CDN layers can serve an outdated version of your sitemap to validation tools, leading to 'URL count mismatch' if new URLs haven't propagated. Always verify the sitemap directly via curl or a browser to ensure you're seeing the live version the validator is likely fetching. Second, subtle character encoding issues (e.g., a Byte Order Mark, or BOM, in UTF-8) or malformed special characters within URL <loc> tags can cause parsers to choke, leading to 'missing required tag' errors even if <loc> is visually present. Ensure your sitemap generation logic rigorously validates and encodes all URLs. Finally, some validation tools have strict timeout settings or limited fetch capabilities, which can result in incomplete reads of very large sitemaps, again manifesting as count mismatches. A common debugging step is to check your server access logs for requests from the validation tools to ensure they are fetching the full, latest version. What specific method are you using for your dynamic sitemap generation?