AttributeError on integral antiderivative form

[satels]

http://www.sympygamma.com/input/?i=integrate%28xcos%28-nx%29%2C+%28x%2C+-pi%2C+0%29%29

 Antiderivative forms:
There was an error in Gamma. For referencethe last five traceback entries are:
Traceback (most recent call last):
File "/base/data/home/apps/s~sympy-gamma-hrd/24.376529677133784673/app/views.py", line 278,
in eval_card result = g.eval_card(card_name, expression, variable, parameters)
File "/base/data/home/apps/s~sympy-gamma-hrd/24.376529677133784673/app/logic/logic.py", line 322, in eval_card result = card.eval(evaluator, components, parameters)
File "/base/data/home/apps/s~sympy-gamma-hrd/24.376529677133784673/app/logic/resultsets.py", line 117, in eval result = card.eval(evaluator, components, parameters)
File "/base/data/home/apps/s~sympy-gamma-hrd/24.376529677133784673/app/logic/resultsets.py", line 98, in eval return self.card_info['eval_method'](evaluator, components, parameters)
File "/base/data/home/apps/s~sympy-gamma-hrd/24.376529677133784673/app/logic/resultsets.py", line 636, in eval_integral_manual components['variable'])
AttributeError: 'ExprCondPair' object has no attribute 'is_polynomial' 

[sahilshekhawat]

This issue has already been addressed in #54 and you might to reload the page sometimes to see the inconsistency.