[Filter] Xpath unknown nodetype number error on flow install

[Hooghof]

Describe the bug
The filter step in this flow contains this xpath expression: //line/number() = 1. It leads to this error:

Failed to create route: 695d2dd5f71686000c000172-85bb8bfb-f354-4856-94c9-15014f1bd21b at: >>> step -> [[Filter[{{language}}{{{expression}}} -> [to[{{out}}]]]]] <<< in route: Route(695d2dd5f71686000c000172-85bb8bfb-f354-4856-94c9-15014... because: javax.xml.xpath.XPathExpressionException: javax.xml.transform.TransformerException: Unknown nodetype: number

To Reproduce
Call the flow:
curl --location 'https://next.dovetail.world/test/inbound_http/regressiontests/Filter_xpath_header' \ --header 'Content-Type: application/xml' \ --data '<lines> <line>1</line> </lines>'

Expected behavior
Same result as on 4.17.10:
<lines> <line>1</line> </lines>

Flow
Name: Filter_xpath_header
Version: 1
Tenant: Regression Tests
URL: https://next.dovetail.world/flowdesigner/695d2dd5f71686000c000172/1/flow

Screenshots
Not applicable