The interactions of the low-pass filters, or output filters, present in multiple power electronics converters (PEC) connected to an electric grid create conditions to the circulation of high-frequency current among the passive elements of the filters. It is verified by simulation and field measurements that such current can achieve significant values if the converters are connected in the same feeder or next to the other. Power quality analyzers (PQA) may not record the high-frequency component, which is related to the switching frequency. At some cases, however, PQA records incorrect harmonics measurements as a side effect due to the electrical variables contain high frequency spectral components and the sampling rate designed for the PQA. The conclusion is that existing PQAs may be not prepared to correctly identify and quantify the high-frequency components that are most probably present in the modern electric networks, and in microgrids, with many PEC-based distribution energy resources.