Duplicate symbols via 2 dependent versions of ooxml-schemas

Using vaadin spreadsheet it pulls in 2 versions of ooxml-schemas. This causes Jetty to complain massivly about duplicate symbols.
Here is a dependency tree. Do I need both 1.1 and 3.15 ? Having 2 jars with the same classes in them is generally not a great idea.

+--- com.vaadin:vaadin-spreadsheet:2.1.0.alpha1
|    +--- com.vaadin:vaadin-server:8.0.0 -> 8.6.0.rc1 (*)
|    +--- com.vaadin:vaadin-client:8.0.0 -> 8.6.0.rc1
|    |    +--- com.vaadin:vaadin-shared:8.6.0.rc1
|    |    +--- com.vaadin:vaadin-server:8.6.0.rc1 (*)
|    |    \--- com.google.gwt:gwt-elemental:2.8.2
|    +--- com.vaadin:vaadin-themes:8.0.0 -> 8.6.0.rc1
|    +--- com.vaadin:vaadin-client-compiled:8.0.0 -> 8.6.0.rc1
|    +--- org.apache.poi:poi:3.15
|    |    +--- commons-codec:commons-codec:1.10
|    |    \--- org.apache.commons:commons-collections4:4.1
|    +--- org.apache.poi:poi-scratchpad:3.15
|    |    \--- org.apache.poi:poi:3.15 (*)
|    +--- org.apache.poi:poi-ooxml:3.15
|    |    +--- org.apache.poi:poi:3.15 (*)
|    |    +--- org.apache.poi:poi-ooxml-schemas:3.15
|    |    |    \--- org.apache.xmlbeans:xmlbeans:2.6.0
|    |    |         \--- stax:stax-api:1.0.1
|    |    \--- com.github.virtuald:curvesapi:1.04
|    \--- org.apache.poi:ooxml-schemas:1.1
|         \--- org.apache.xmlbeans:xmlbeans:2.3.0 -> 2.6.0 (*)

I tried excluding schemas:1.1 – result is chart breaks.