I am currently doing some research and encountered this issue in one my SEM-analysis. The full SEM model has a very high explained variance (Squared Multiple Correlations) for the explained latent variable.

Here is the full SEM model:

The output is here: (pdf).

The model fit is not exactly great, hence I wonder what possible explanation there could be for the high explained variance. My current idea is that some of the latent indicators have cross loadings on the indicators, but otherwise I am stumped!