Hello general,
There are multiple reasons of this behavior, two of them are data feed specific:
1.
IB Pacing Violation;
2. IB API sometimes becomes unresponsive - this case has been already reported to IB support - there has been no confirmation/solution for it yet;
3. Some MultiCharts data handling internal issues. We have resolved these issues and improved the data loading algorithms. The improvements will appear in MultiCharts 9.0 beta 1. That should speed up MultiCharts communication with the data providers' interfaces, but that will not solve the reasons outside of MultiCharts (#1 and #2).