start width > end width is ignored when using the "exact" color interpolation method

[DelazJ]

What is the bug or the crash?

When applying the interpolated line symbol, with both varying width and varying color, if the start point's width value is greater than the end point's, the output with exact color interpolation method does not take it into account; the end point is always assigned the max width instead.

Steps to reproduce the issue

In the screen cast, I'm trying to get big blue circle on the starting point (the one at the bottom). As you can see, contrarily to the other color methods (where the start point gets bigger size), the rendering with exact method does not change if I switch start and end values (the big circles are always near the end point)

Versions

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QGIS version	3.22.0-Białowieża	QGIS code branch	Release 3.22
Qt version	5.12.8
Python version	3.8.10
GDAL/OGR version	3.0.4
PROJ version	6.3.1
EPSG Registry database version	v9.8.6 (2020-01-22)
Compiled against GEOS	3.8.0-CAPI-1.13.1	Running against GEOS	3.8.0-CAPI-1.13.1
SQLite version	3.31.1
PostgreSQL client version	12.8 (Ubuntu 12.8-0ubuntu0.20.04.1)
SpatiaLite version	4.3.0a
QWT version	6.1.4
QScintilla2 version	2.11.2
OS version	Ubuntu 20.04.3 LTS
Active Python plugins
trackable_project_files	v1.2.2
MapsPrinter	0.6
MemoryLayerSaver	4.0.4
db_manager	0.1.20
processing	2.12.99

Supported QGIS version

• I'm running a supported QGIS version according to the roadmap.

New profile

• I tried with a new QGIS profile

Additional context

No response