Mysterious “not a consistent list of real values” error from FindPeaks

Question

I am working with temporal data objects and experimenting with FindPeaks. I find that the function sometimes fails with the error

FindPeaks::arg: The argument TimeSeries[] at position 1 is not a consistent list of real values.

See for example the following time series:

in = {{3685681800, -2132.95}, {3685682100, -2133.78}, {3685682400, -2130.24}, {3685682700, -2129.87}, {3685683000, -2130.27}, {3685683300, -2128.06}, {3685683600, -2128.38}, {3685683900, -2128.75}, {3685684200, -2129.35}, {3685684500, -2130.29}, {3685684800, -2130.16}, {3685685100, -2133.46}, {3685685400, -2133.9}, {3685685700, -2132.86}, {3685686000, -2133.03}, {3685686300, -2132.51}, {3685686600, -2131.83}, {3685686900, -2130.02}, {3685687200, -2130.47}, {3685687500, -2130.8}, {3685687800, -2130.12}, {3685688100, -2130.42}, {3685688400, -2131.01}, {3685688700, -2130.18}, {3685689000, -2128.85}, {3685689300, -2129.86}, {3685689600, -2130.65}, {3685689900, -2131.3}, {3685690200, -2130.24}, {3685690500, -2131.8}, {3685690800, -2131.56}, {3685691100, -2131.39}, {3685691400, -2130.51}, {3685691700, -2129.95}, {3685692000, -2130.17}, {3685692300, -2130.07}, {3685692600, -2128.77}};

inTS = TimeSeries[in];

FindPeaks works some some levels of Gaussian blur but not others.

FindPeaks[inTS, 1] (*fine*)
FindPeaks[inTS, 2] (*fine*)
FindPeaks[inTS, 3] (*fine*)
FindPeaks[inTS, 4] (*fine*)
FindPeaks[inTS, 5] (*fine*)
FindPeaks[inTS, 6] (*fine*)
FindPeaks[inTS, 7] (*fine*)
FindPeaks[inTS, 8] (*fine*)
FindPeaks[inTS, 9] (*fine*)
FindPeaks[inTS, 10] (*ka-boom!*)
FindPeaks[inTS, 11] (*fine*)

I am working with a large number of data sets, and can't manually tune for each one. Why this is the error appearing and what can be done about it?

Answer 1

This is more of an extended comment rather than an answer.

For $\sigma=10$ no peaks are found. You can see what happens as $\sigma$ is changed in the following:

Manipulate[
 peaks = FindPeaks[in[[All, 2]], σ];
 gf = GaussianFilter[in[[All, 2]], σ];
 ListLinePlot[{in[[All, 2]], gf},
  Epilog -> {Red, PointSize[0.04], Point[peaks]}],
 {σ, 1, 15, Appearance -> "Labeled"}]

Using

FindPeaks[in[[All, 2]], 10]

returns {} whereas

FindPeaks[inTS, 10]

returns the error you see.