According to research:
Oxalates: both spirulina and AFA contain naturally occurring oxalates in low amounts compared to other plant based foods like spinach or rhubarb. Journal of Agricultural and Food Chemistry (Chu et al., 2002)
Lectins: both spirulina and AFA contain lectins but are in amounts so low it is unlikely to cause issues when consumed as part of a balanced diet. Journal of Applied Phycology (Guzman-Garcia et al., 2016)
Phytates: as with most plants, including algae, spirulina and AFA both contain phytates in lower amounts than most plant based foods. Journal of Science of Food and Agriculture (Vazquez et al., 2006)
Conclusion:
While Spirulina and AFA do contain oxalates, lectins, and phytates, their levels are generally low compared to most other plant-based foods. To mitigate the potential negative side effects of these anti-nutrients, it's essential to consume a varied diet that includes a wide range of nutrients, and maintain a balanced diet.