This warning is not correct:

Creating DFDL Test Suite for file:/home/mbeckerle/Documents/dataiti/git/NGF-daffodil/eclipse-projects/test/target/eclipse/classes/edu/illinois/ncsa/daffodil/section16/array_optional_elem/UnparseArrayImplicitOptionalElem.tdml
Schema Definition Warning: dfdl:lengthKind 'implicit' is not consistent with dfdl:length specified (as 1). The dfdl:length will be ignored.
Schema context: ex:r4 Location line 90 column 6 in file:/tmp/s1_6354187969998608971.dfdl.xsd

In that TDML file, the length="1" is in the default format.

This warning is acceptable if the length is explicitly expressed on an element of lengthKind 'explicit', but not if the length is taken from surrounding default format. In that case the length should just be ignored unless lengthKind is explicit.