Expressions don't work for E motor values

[Olby]

Think I found a bug/limitation in the expression code. Verified using the latest beta (3.2-beta3.2).

This expression is accepted, but doesn't update the E value:

M906 E{0.7*sqrt(2)*1400}

This one works:

M906 Z{0.7*sqrt(2)*1680}

Tested with expression for both my E with the same result.

M906 E{0.7*sqrt(2)*1400}:{0.7*sqrt(2)*1400}

Is this a known limitation?