Head merge resets meta to default if the tag is not present in turbo response

I noteced that if I don’t include <meta name="turbo-prefetch" content="false"> with every response – turbo-frame navigation restores it back to true and starts to issue fetch requests on link hovers.
Is this intentional? My first intuition is this shouldn’t be so, imo merge should change existing value only if a tag with a new value is present. What do I miss?