Some default values are not stored

If I go to the "Product Filter" tab and Edit one of my categories to set default values, the values I input is not always stored (depending on the value).

For example, if I want to set the default value for "Custom label for Shopping Campaigns 0":
I input the string 1,5 and it is stored correctly.
However, if I input 1,50 it stores an empty string is the default value.


Log for the value 1,5 (success):
--------------------------------------------------------------
2019.04.14 00:11:36:4612*******
FeedsController. ProductFilterValuesEditPopup. CategoryId=33, ProductId=0, FeedCategoryId=2, FeedProductId=0, FeedId=1, TypeActiveId=1, CategoryMap=Toys & Games, ASIN=, EPID=
2019.04.14 00:11:36:4629*******
FeedManagerAttributeParser. AddDefaultValues. attributes=, defaultValues.Count=
         FeedAttributeId=31, Value=1,5

2019.04.14 00:11:36:7754*******
FeedManagerAttributeParser. ParceDefaultValuesXML. feedId=1, defaultValuesXML=<DefaultValues><DefaultValue><FeedAttributeId>31</FeedAttributeId><Value>1,5</Value></DefaultValue></DefaultValues>
         FeedId=1, FeedAttributeId=31, FeedName=custom_label_0, Value=1,5, IsRequired=False, AdvancedField=True

Log for the value 1,50 (failure):
--------------------------------------------------------------
2019.04.14 00:13:14:4927*******
FeedsController. ProductFilterValuesEditPopup. CategoryId=33, ProductId=0, FeedCategoryId=2, FeedProductId=0, FeedId=1, TypeActiveId=1, CategoryMap=Toys & Games, ASIN=, EPID=
2019.04.14 00:13:14:5083*******
FeedManagerAttributeParser. ParceDefaultValuesXML. feedId=1, defaultValuesXML=<DefaultValues><DefaultValue><FeedAttributeId>31</FeedAttributeId><Value>1,5</Value></DefaultValue></DefaultValues>
         FeedId=1, FeedAttributeId=31, FeedName=custom_label_0, Value=1,5, IsRequired=False, AdvancedField=True

2019.04.14 00:13:14:5083*******
FeedManagerAttributeParser. AddDefaultValues. attributes=, defaultValues.Count=


I'm using NopCommerce 4.0 and Feed Manager 1.63

I need to investigate this problem....