Sounds like your line was cut and is now impacted due to a splice.
Odd comment. A single extra joint done correctly (it's hard to get wrong) will have no noticeable impact on a lines sync.
It isn't exactly detrimental to a line to have joins/crimps or everyone on copper would be screwed.
Count the number of footway "joint boxes" (the clue is in the name) on the average pavement and how often they are spaced.
Most lines probably have half a dozen joints between cabinet and home. Lots have many many more.