Shouldn't there be only one tone right in a word?

In 情形 you can click either 2nd tone or neutral tone for the character 形, and it is both marked right. I know the character normally has the second tone, but in this word it is neutral. So shouldn't the second tone be marked wrong here?

It'll be second tone in Taiwan I imagine.

That's the reasoning given for this occurrence in general - if there are multiple pronunciations between different locales (generally 普通话 versus Taiwan Mandarin), both tones are generally accepted on Skritter.

I think that's a good thing, particularly when so many of those neutral tones are rather toned-down versions of their originals in practice rather than actual neutral tones.

I often come across words like this. For example 势力 and 势利. I am not sure if there really is a correct pronunciation, since I have found in different dictionaries some give the final li a 4th tone and some not.

I think there are some words however where we can say for certain that the character's tone in not pronounced. For example 胳膊的膊

As for the difference between learning Taiwanese and mainland pronunciation, I might be wrong, but I guess that most people here are learning the later rather than the former.

Ok, good to know. Are there actually big differences between Mainland Mandarin and Taiwan Mandarin. Is there a good online dictionary, where you can look this up?

What bothers me more about this is that it is not consistent in skritter. For reading practice there is always only one correct one (even in cases where there are more correct ones).

“It'll be second tone in Taiwan I imagine.”

Some basic information on 轻声 in Taiwan (http://zh.wikipedia.org/wiki/%E7%8F%BE%E4%BB%A3%E6%A8%99%E6%BA%96%E6%BC%A2%E8%AA%9E):

Traditional:
根据中華民國教育部标准，轻声出现的情况要比中国大陆标准略少。在上述情形中，轻声可读可不读且意义无差异时，台湾国语标准一般不作轻声处理。 需要指出的是，中国大陆南方人、台湾人和東南亞華人在使用現代標準漢語时，受其方言影响，使用轻声的频率要比上述标准低得多，不少人甚至几乎不使用轻声。但由于在大多数情况下并不影响交流，因此也可将其视为廣義上的現代標準漢語。

Simplified:
根据中华民国教育部标准，轻声出现的情况要比中国大陆标准略少。在上述情形中，轻声可读可不读且意义无差异时，台湾国语标准一般不作轻声处理。 需要指出的是，中国大陆南方人、台湾人和东南亚华人在使用现代标准汉语时，受其方言影响，使用轻声的频率要比上述标准低得多，不少人甚至几乎不使用轻声。但由于在大多数情况下并不影响交流，因此也可将其视为广义上的现代标准汉语。

There's also information on 儿化音:

根据中华民国教育部标准，儿化出现的情况要比中国大陆标准少得多，除“这儿”等少量词语外，台湾国语标准一般不作儿化音处理。

I made a suggestion before that it would be great if the user could pick which tone would be correct and then Skritter would only count that tone as correct (for example, if my textbook/teacher/wherever I speak Chinese says something should be neutral, Skritter would only count it right if I used neutral, but somebody else could study the same word and use a different tone because that is right for the other person). I think it's just too complicated with the coding to implement a feature like that. Just one of the joys of studying Chinese I suppose.

I still have it on my list to make it so that reading practice implements the same neutral tone / full tone option as normal tone practice does, but it's coded very inconveniently for me to do that, so I haven't done it yet.