Divison by zero error for series

[Michael Jung]

Consider the following (analytic) function:

sage: a = sqrt(x)/(2*sinh(sqrt(x)/2))
sage: a.taylor(x, 0, 10)

91546277357/420928638260761696665600000*x^10 - 5749691557/669659197233029971968000*x^9 + 16931177/49950709902213120000*x^8 - 8191/612141052723200*x^7 + 1414477/2678117105664000*x^6 - 73/3503554560*x^5 + 127/154828800*x^4 - 31/967680*x^3 + 7/5760*x^2 - 1/24*x + 1

However, the series command returns a division by zero error:

sage: a.series(x, 10)

Traceback (most recent call last):

...

ValueError: power::eval(): division by zero

This is not supposed to happen right?

Best,
Michael