In Foxvog's Sumerian grammar, he assumes that the ergative marker -e was pronounced as -e, even after the possessives -(a)ni and -bi. For example, he transcribes "her king" in the ergative as lugal-(a)ni-e > lugal-a-né, and "its king" in the ergative as lugal-bi-e > lugal-bé.
However, the cuneiform signs né and bé are more commonly read as ni and bi. And distinct, commonly-used signs for ne and be certainly existed in the syllabary. The fact that the Sumerians chose to use the NI and BI signs instead of NE and BE seems like a reasonably solid indication, to me, that the actual pronunciation was
/bi/. And this is backed up by looking at how it combines with other possessives: lugal-ŋu-e "my king" > lugal-ŋu₁₀, with no
/e/ in sight.
So, why does Foxvog read lugal-a-né and lugal-bé instead of lugal-a-ni and lugal-bi? I assume he knows what he's talking about and has a reason for writing it this way, but his grammar doesn't really present any rationale for this decision.