This problem may arise due to peculiarities of Adobe Flash Player: if you apply zoom in action several times to SWF file that contains filters, they are likely to disappear. You may fix this problem (if it occurs for optimized files) by setting Shapes Ratio, Shapes Morphing Ratio and Fonts Shapes Ratio values (may be found in Optimize objects tab) to something between 10-20% or completely disable Transform Shapes, Morphs and Fonts options in Current optimization set tab.