addNextSibling() results in "pointer being freed was not allocated"

[AndroidGecko]

Description:

After using addNextSibling method. Application crashes during XMLDocument.deinit

deinit {
        xmlFreeDoc(self.docPtr)
    }

with malloc: *** error for object 0x7fee7f04465b: pointer being freed was not allocated

What I want to do?
I want to replace few nodes with new ones in xml.

How I am doing it?

if let doc = try? HTML(html: content, encoding: .utf8) {
    for media in doc.xpath("//replace-tag") {
                let img = "<img />"

                if let imgTag = try? XML(xml: img, encoding: .utf8) {
                    media.addNextSibling(imgTag.xpath("//img")[0])
                }
}

If I remove the addNextSibling method call, all works.
Before deallocating XMLDocument I can see that doc has properly attached img tags as in code.

Installation method:

• Carthage
• CocoaPods
• Swift Package Manager
• Manually
• other: ()

Kanna version (or commit hash):

4.0.0

swift --version

4.2

Xcode version (optional):

10.1

[AndroidGecko]

when building locally and removing

deinit {
        xmlFreeDoc(self.docPtr)
    }

all works